(1

Chapt I var. under domest

p

16 What is domestication—changed conditions

19 — anyhow some slight variation must be admitted.

20 changes in the individual

21 congenital variation

22 Hereditariness— why one thing inherited & not another— Mutilations, effect a need, not hereditary

25 atavism 27 Peculiarities attached to sex 27 variation appearing at same age

29 causes of variation—Direct Immediate causes 31 Habit 32 variation from simple organisation 34 Indirect effects, making organs plastic

35 Laws regulating variation— Balancement—nisus formativus 37 Effect of homologies

38 mechanical relations—arrests — 39 cohesions — p. 40 multiple organs varying in number p 41. variations analogous to other species & to other varieties 41 Correlation of growth & constitution—obscure relations, as colour & constitution

p 43 Effects of crossing in obliterating & forming races; selection required for do

p 47 Selection, produces effect of adding up small changes p. 50 Breeds are true; 51 antiquity of selection— p. 54 unconscious selection: p. 55 constitutional or natural selection: p. 56 acclimatisation of plants 58 condition circumstances fav. & unfav. to selection; non-varying 62 Facility in preventing crosses 64 Effects of selection on natural results: 67 Effects of selection as shown in flowers & fruit compared.

Chapt II var. under domest. (continued)

3. general argument whether plants so much altered by domest. as not to be recognised; steps in cultivation by savages—why certain countries have not produced useful products.

N.B why not animals domesticated— we do not want them. Goats & Asses

10 The Cabbage 13 Dog} sport in Plant? isolation

18 — changes within historical times

20 Cat

22 Horse

26 Pig

30 Cattle

38 Sheep & goats

40 Rabbit

43 Fowl

46 Ducks

50 Pigeons

57 Tumbler

62 Runts

52 Pouter

59 Turbit

65 Dovecots &c

54 Fantail

60 Barb

68 Imperfectly known breeds

56 Jacobin

61 Carrier

69 Amount of important differences

70 Individual variability

[1v]

[faint pencil note:] I think here all naturalised animals—P. Santo Rabbits—Mice in different countries—Naturalisation Cardoon—Naturalised plants in N. America.

(2

Ch. 2

Pigeons. 74 History of changes of Principal Breeds

76 g. Discussion on Origin

77 How many Rock Pigeons

81 C. livia parent race

83 Not feral: fertility

85 Reversion to Blue Breeds

90 C. livia parent race, reasons for

92 Circumstances: antiquity &c, favourable to most variation, Pigeons

94. Probable steps in the variation; 96 Probable sports in Pigeons

103 Summary; varieties like species: man can not select internal changes, only conspicuous

107 Summary that multiple origins not general; for breeds abnormal, & no reason why such selected & such extinct. 109. Argument from peculiar races, when no peculiar endemic species. 110 Argument from general fertility of mongrels

111 Antiquity of animals & plants; 114 summary on do.

118 Summary on breeds resumed; differ in variability

120 Objections, from assumed force nature 123 Especially plastic 124 variation limited

126. Summary on objections & close of chapter

Ch. 3. on possibility of all organisms crossing: on susceptibility of reproduction to Change

1. Ill‐effects of interbreeding. p. 3 opposed facts * in islands

5 Good from crossing in plants; 7 even in hybrids

11 Good from slight changed conditions— 13 opposed facts— 14 good in animals

16 No land animal real hermaphrodite

18 Flowers rarely are fertilised sub jove. 19 hermaphrodites & unisexual in same groups

20 All animals can cross

26 All plants can cross 26 bis Dichogamy

27 varieties of plants do cross freely

28 great care taken by hybridisers to prevent crosses

31 On pollen carried by wind & insects— 32 insects necessary to fertilisation *How bees find flowers

37 Bees frequent visits— 39 Pollen brought to Thyme & Rhod:

41 Opposed fact to crossing of plants; fertil in buds, Campanula &c

44 in wheat, vars. not crossing

46 Trees with separated Sexes

47 bis Subularia, Podostemon 48 Goodenia 49 Aristolochia & Arum

(3

Ch. 3 continued. Crossing & sterility

50 Hollyocks 52 Orchidaceæ 56 Ophrys.

58 Leguminosæ 62 opposed facts

64 Summary on probability of crossing occasional in animals & plants

66 Superfluity of pollen — 68 Crossed offspring better chance of surviving

70 Final cause of crossing

72 Changes of condition causing lessened fertility

74 in animals 78 In birds, 83 effects on Secondary male characters & instincts

84. effects in domesticated animals: not explained by disease &c

86 in plants, 89 Can stand great changes in temp, & domestic plants

90 Contabescence

93 Double flowers, great fruit & tubers: 95 parallelism in Hybrids

97 Domestication & Cultivation itself not stop fertility. Doubleday (*Wild flowers not seeding in own country

100 Conclusion.— 101. Bears on Variability & on early period of Cause of.

Ch 4

p. 1. Definition of Species Antiquity of variation under nature of shells in Madeira must be included in this chapter

6 Different kinds of variation — p 8. sub-species—gradation from species to individual differences

10 impossible to tell how far variations inherited

12 Naturalists practically are guided by having intermediate forms

14 Naturalists forms between good species. 15 Watson's categories

16 Individual differences, 17 Graba's — 18 are they of the same class as differences constituting recorded varieties?

21 genera variable in one country, variable everywhere?

24 Cases of individual variability

35 Difficulty in deciding what are species not due to want of knowledge: British plants: numbers estimated

37 Brehm.

38 Difficulty increases when specimens brought from many districts

39 difficulty a climax, when specimens taken from separated regions: but what distance is enough to make 2 regions distinct

41 Conspicuous animals & plants generally are perceived to vary

44. conspicuous & useful plants not cultivated

⸮⸮ Feral animals & plants not domesticated

48 Marked vars, Elephant 50 Foxes 53 Raven, Carrion & Hooded Crow

56 Tetrao Scoticus — 59 Guillemots — Madeira Black-cap

60 Carp 61 Wollaston's insects

Plants 63 Centaurea, Taraxicum, Isatis 64 Festuca, Polygonum 65

65 Myosotis Azores Tolpis 66 Digitalis, Iris 67 Anagallis 68 Primula

80 Conclusion: my definition of "species".—

3 bis

Chapter 4

p 1 wide ranging and common and much diffused species tend most to vary.

p. 6 (8) D'Archiac's rule not really opposed.

7 (10) Geographical range of varieties themselves

10 (14) Relation of common species to large size of genera

13 average range of all the species in the larger genera not greater than in the smaller genera.

14 Highly organised beings have acquired narrow ranges.

15 (20) Species having recorded varieties are more frequent in larger than in smaller genera. 16 (23) The species in large genera are themselves closely allied.

22 (30) Reason why Prodromus not good.

27 (35) Why I disregard other difficulties.

32 (41) Summary on discussion.

[in another's hand:] pagination in square brackets = orig. MS

(4

Chapt. 5. Struggle for existence.

2-5 Mere variability will not account for wonderful structures

9 Struggle for existence

10 Rate of increase p. 12 In feral animals & wild under good circumstances

15 cannot be explained by altered fertility

17 All animals breed

18 Checks to increase in animals p 24 odd checks 25 in birds 29 Colonies destroyed

30 Definition of term Struggle for Existence

31 Facts in distribution explained by struggle in Animals 33 Complicated

34 Rate of decrease, compensation

37 Checks, Animals & Plants

41 Checks Plants & Plants; 44 not limited absolutely by temperature

47 Herbert on Struggle 48 Maer Heath case 50 Rotation, influence of 53 Slight causes determining victory

55 Struggle severest between individuals of same species.

55 (E) Facts opposed to Struggle: local species common: Madeira Helix cases; explained 58 Plants social on limits of range

59 Explained by mutual protection 61 fertilising each other

p. 63 monstrosities in nature, appearing to show no struggle

65. numbers not dependent on number of eggs or seed

66 Summary brief

70 Corollary, that structure is related most intimately in organism to organism

Chapter 6. Natural Selection.—

4 very slight differences can be selected 7. Selection may act on larvæ or Sexes

7(b) Sexual selection 7(k) In Plants

8 Effect of change of climate on continent p. 11 as it places open shown by naturalised productions

12 Imaginary illustrations: Catskill wolves—flowers & Bees— Dioicous

[For readability, the section below is left uncrossed]

19 Comparison of man's and nature's selection. 26 Extinction & Divergence plays part.

28 Crowd of Difficulties

33 Causes favourable & unfav. to Selection 35 Isolation (38) in regard to Intercrossing

41 Illustration of isolation & intercrossing in Madeira & Galapagos

43 Varieties keeping separate — 46 In plants

49 Intermediate variation rare — 50 only not met with some Continents

5449 Large number of individuals favourable for selection

56 Summary on causes fav. & unfav. — 59 Malay Arch. illustration.—

51 Slowness of Selection

63 They applied to Races of man

(4. bis

19 Comparison of man's and natures Selection

26 Extinction

26c Principle of Divergence: in domestic animals (d) Amount of life due to diversity shown by culture & by natural distribution (h) shown by naturalisation (l) shown by physiological division of labour (p) Divergence acting in nature on large genera (s) Diagram of (w) varieties how supplant parents (aa) varietal differences become specific (cc) bears on classification (gg) limit to total number of species in any country (mm) classification compared to Tree of Life

28 Crowd of Difficulties

33 Causes favourable & unfavourable to Selection 35 Isolation 38 Intercrossing

41 Illustration of isolation & intercrossing in Madeira & Galapagos

43 Varieties keeping separate 46 In plants

49 Large number of Individuals favourable for Selection

51 Slowness of Selection

53 absence of intermediate Links; nature of such Links

54 Links chiefly extinct

57 Links generally absent now when species mingle in border regions

58 Areas perhaps not formerly continuous

60 Conditions of continuous areas do not really graduate insensibly

62 Intermediate varieties rare

64 [do] varieties tend to be easily exterminated

Summary—illustrated by Malay archipelago.

(5

Chapter 7 Laws of Variation: Varieties & Species compared.

p. 4. immediate action of external causes: heat, brackish water, depth, proximity to Sea

p. 8 analogous variations under different conditions

10 Acclimatisation of species 13 Species naturally extending Range

19 Effects of Use & Disuse—flight Birds (p. 22) Insects 26 Tarsi 28 Blindness in moles — 32 in fishes

34 Correlation of growth — multiple parts varying 35 Homologous parts varying in like manner — & to unite — teeth & hair — seeds of Umbelliferæ & Compositæ

39 Early monstrosities & change must affect subsequent parts

41 Brulle's law, that most metamorphosed parts are modif developed first. Bears on M. Edwards

45 Balancement

52 Extraordinarily developed parts are variable 59 Cases

70 Summary on: explanation of

77 Rudimentary Parts variable

79 Monstrosities: arrests of Development — do not produce new species

86 Distinct species present analogous varieties: vars of one resemble normal character of other species. Reversions: 90 analogous vars in nature — 95 Cases of vars mocking species — 105 Horse case

114 Distinctive characters of varieties more variable than specific, & Specific characters more variable than generic: sexual & specific differences allied.

Characters variable &c

Chapter 8. Difficulties in Transitions.—

2. How could Bat be formed? Birds gradation in flight p. 9 Diversified habits in same species, & different species of genus

p. 12 change of Habits in introduced organisms, & in nature in different regions

17 organisms with intermediate habits likely to be rare

19. Habits not conforming to structure: Upland Geese — 22. does not appear like creation.

25. Could so perfect organ as eye be formed? 33 must admit any nerve; could be made acoustic or optic

35. Do quite new organs appear? "Natura non facit saltum". Kinds of transitions 37 changes in function — 39 two organs with same function 41 changes in function same organ with two functions — 42 functions changing with age or condition, or always in two states

45 Cases of difficult transitions, generally only apparent: Poison glands of snakes 50 separation of Sexes

53 chemical compounds definite 55. Neuter insects (58 How sterile) (61 How acquire their structure

76 Summary on transitions—natura non facit saltum explicable on our theory

77 Similar organs in remote animals, as Electric organs in fish.

81 Cd organs of little importance be formed by selection? causes of error, attribute to selection what not due to it. 83 fly-flapper—eye-lashes; how selection may act on them,

(85) when more important to ancestors, or concurrently with other advantages.

(6

Chapter 8. continued. Difficulties on Transition

p. 86. Some have protested against utilitarian view of all organs.

88 Selection will produce nothing injurious: 89 Organisms are not perfect

93 no structure can be modified for good of other species

97. as Result of whole accords with Cuvier's principle of Conditions of Existence

97 Difficulty from supposing Bird, fish, & mammal have had common ancestor— 99. Summary.

Chapter 9 Hybridism & Magnetism.

p. 4. Final cause of sterility of hybrids & first crosses: distinction between which.

Plants

9 Species when first crossed generally sterile; Gærtner's method: 10 ill-effects of Processes

10 Sterility of hybrids, only in function: even sterility during reduction: 14 when self-fertilised

16 Sterility in successive generations partly due to interbreeding, evidence of.

18 W. Herbert's cases of fertile hybrids & first crosses: 21 [insertion:] Lobelia Even excess of fertility; & Gærtner's cases of do

24 Florists' crosses very fertile: 27 Conclusion is that sterility not universal attribute of Species.

28 Difficulty of distinguishing species & vars of plants by fertility, compared with other evidence.— Cases

36 Infertility of vars (plants) when crossed; 42 explanation & difficulties in getting evidence of this.

44 Laws & circumstances governing infertility: gradations of sterility: 46 affected by conditions & innately variable: 48 Related to systematic affinity 50; not governed by external form or constitution: 51. Reciprocal crosses

55 no absolute relation between fertility of first crosses & hybrids 56 good case

57 special odd cases; mother's pollen gives fertility quickest: male organs fail first

58 Exceptional & Decided types sterile 60 prepotency & fertility do not go together.

64 Conclusion that sterility is an incidental quality like 65 Grafting

70 Causes of Sterility, in first crosses, from distinct causes; 72 In hybrids compared with that from changed conditions

78 Animals: instinct comes into play; aversion rare: 80 fertility of first crosses & of hybrids compared: reciprocity doubtful: 83 male sex fails easiest, gradation in sterility 83 affected much by all conditions: 85 not governed by systematic affinity: 88 Table of Rasores.

89 Cases of the most fertile hybrid animals: 98 summary: reason for expecting much sterility in animals, from confinement & interbreeding

99 Domestication increasing fertility of first crosses & of Hybrids

101 Fertility of crossed varieties & of their mongrels 104 difficulties in subject

105 in Pigeons 107 Explanation; owing to difference in natural & artificial selection.

(7

Chapt 9 Continued: Hybridism

p. 110 Hybrids & Mongrels compared, independently of Fertility.— Plants:

— Hybrids are not monsters: 112. Gærtner's difference of mongrels more variable in first generation 115 variability of Hybrids in successive generations: 116 neither hybrids or mongrels universally variable: 117 Reversions:

118 Alike from reciprocal crosses. Rules of resemblance: 119 Prepotency

120 Reduction—Old vars not prepotent over new: 121 Two close species crossed with third, compared with two varieties in do. Laburnum Case

123 Animals: difficulties from complex laws of inheritance

124 I. St. Hilaire's law, hybrids fixed, mongrels heterogeneous & like either parent: 126 Hybrids heterogeneous — 127 Hybrids heterogeneous in successive generations — 127. Mongrels usually intermediate, exceptions

128 Mongrels sometimes, though rarely, have fixed character

129 Laws of resemblance, part after Father false, but same for species & varieties — 130 Characters, as colours, suddenly appearing are transmitted either whole or not at all

132 Prepotency of species over species & race over race 133 Trumpeters

134 In individuals. —134 Bis Prepotency of old Race over new, doubtful — 135 Reduction in birth, rate of. —

136 Quagga case — 137 Summary of rules for Animals & Plants, for hybrids, mongrels, & Individuals

138 Summary for whole chapter.

Chapt. 10. Instinct.

3. Characteristics of.— 7. none universal 10. Intellect of animals

14 degree to which end of instinct is recognised. 15 performed by the young

18 Imitation 22 Comparable with Habits

31 Tricks & Habits inherited by domestic animals. 37 not strictly acquired by Habit but by selection of self-originating peculiarities & (p. 41) by training 46 Lost.

49 Instincts of animals in a state of nature

50 Migration

58 Instinctive fear 62 feigning death.

64 Nidification 69 Variations of 78 Habitations of animals

80 Parasitism. 82 Rhea 84 Hymenoptera

86 Social insects 88 Slave makers 92 Bees combs

98 Miscellaneous remarks— variation under different circumstances or times of life

(8

100 Occasional odd habits 102 Reversions.

102 Special difficulty, same instinct in remote classes: 103 not for good of others

104 Instinct performed only once —105 apparently no gradation

106 Trifling instincts: mere tricks

108 imperfect instincts.— 113 Conclusion.

(1

Chapter 3.

on the possibility of all organs being, occasionally crossing. & on the remarkable susceptibility of the reproductive system to external agencies..—

The subject of the present chapter is related t to some degree to points discussed in the previous chapters as to breeds being kept constant by the parsing blending of slight & individual differences as to crossing parsing attributing very slight & distinct characters & varieties & so keeping a broad constant & to those several questions questions which follow, & may therefore be as well intercalated here as elsewhere.

on the ill effects of close breeding in & in. That evil arises from this process carried to an extreme has been so a general an opinion in various countries & times, that it w is universally known.* That general beliefs of this nature have often no foundation is very true; but in this case it may perhaps more readily trusted as the breeder is often most unwilling to act on it his beliefs, as it must seriously interfere with his process of continued selection of some peculiarity in his own stock. (a) the general belief seems to be that (a) decrease in size, & perhaps of general vigour is the first result of close interbreeding, & then lessened fertility. Fanciers in particular lines, who do not take the. Pigeon Fanciers who did not believe in the evil of close interbreeding; & he has the best & from the stock pigeons being easily paired for life, generally shut up,

(U)

[1v]

* Sir G. Grey in his most interesting Journal of Expeditions into Australia vol 2, p. 243 says that anything approaching to the crime of incest is held in abhorrence by the Australians. So it is with the aborigines of N. America, & Dobrizhoffer makes the same in regard to the Abipones of S. America. It is singular that this feeling does not appear to have been felt by the Kingly class of the Polynesians; but Ellis does not doubt that infertility grant evil from followed from their incestuous marriages. (U)

Prescott—Ohio — Chinese of same name.

(a) Independently of the undoubted evil of matching animals having the same infirmity, which must always tend to be the case when relations unite (U)

(2

(Ch. 3. Inter-breeding ills of)

opportunity of judging, from pigeons being easily paired for life, generally shut up, & many generations raised in a short period: when size is an object as in the Pouter, it is asserted (a Treatise on Fancy Pigeon by J. M. Eaton, p. 56) that the ill effects are very soon perceived, not so when small birds are wanted as in the Almond Tumbler; but in these such cases many of the birds become shy breeders.—The high price of fa many fancy dogs, of which have long been closely selected & interbred as Blue haired spaniels, I have been assured is, due more to the difficulty in getting them to breed quickly freely, than in their thro throwing inferior animals; I have known the female requiring to be held, exactly as in the production of some Hybrids* *(Hunter's animal Economy in regard to a she wolf too.)

& indeed if no such difficulty existed the high price of such dogs would be quite inexplicable. The particulars have been told given me of one gentleman who long had kept a small family of blood-hounds, & from being very unwilling to cross his breed, he almost lost them, so infertile had they become, until he was obliged to do so & resort to a cross when his d breed regained the fertility became fertile.

(2

(Ch. 3. ill effects of intermarriage)

& many generations bred in a man's life, a Fancier in this line has good opportunity of judging.

(2 bis

(Ch. 3. ill effects of breeding in & in)

The evidence of an acute man observer like Sir John Sebright, who bred all sorts of animals during his whole life, & who said boasted that he could produce any form feather in years & any fer form in years; & who always worked by crossing & thereby closely interbreeding, is very good; & he was a most firm believer (   ) in the ill effects of this process carried on too long. I was assured by Mr Yarrell that Sir John had for so long interbred his Owl-Pigeons, that he nearly lost his breed whole stock by their extreme infertility: I have seen some silver Bantams, bred from Sir John Sebrights', which in all were nearly as sterile as hybrids for they had laid in that season laid two full nests of eggs, & not not one of which did not produced a single chicken. The cock, also, Bantam had not saddle hackles seemed to have lost its secondary male characters, for it had not saddle-hackle, & was was scarcely more brilliant plumage than the hen. some agriculturalists believe that Bulls lose their

[very faint pencil line:] Andrew Knight. Eng authority whose writing makes me put credit in chapters are [2 words illeg].

(3

(Ch. 3. ill effects of breeding in & in)

On the other hand some competent judges have doubted the ill effects of interbreeding. The case of Bakewells cattle has often been quoted, & it shows that a man with a large flock may continue the process for a considerable time; but Youatt (Cattle p 199) speaking of the subsequent deterioration of this breed says "it had acquired a delicacy of constitution inconsistent with common management" "& many of them had been bred to that degree of refinement that the propagation of the species was not always certain." (U)— In most of the cases of se closely selected cattle & sheep there has been much mystery, & it crosses have been suspected. The English Race horse & Mr. May Meynell's hounds (Karkeek, Veterinary Journal vol. 4. p. 4 & Mr. Appleby in Encyclop. of Rural Sports p. 280 have also been advanced as in instances of pretty close interbreeding without any ill effect. In these cases it may be suspected from what we shall presently see, that individuals being taken to different parts of the country & differently treated, & then occasionally brought together & matched, would lessen the ill effects of interbreeding. Again the case of the half-wild cattle in Chillingham (U)

[CUL-DAR119.- "Veterinary: Jan & Feb. number 1841. Karkeek on the geological History of the Horse".

(4  

(Ch. 3. ill effects of intermarriage)

has be, which none are believed to have been gone on interbreeding for the last 400 or 500 years (Culley on live stock) seems a strong case; but (a) in other & other cases of catt

[slip of paper pasted on:]Lord Tankerville, the owner, expressly states that "they are bad breeders." (British Association Zoolog sect. 1838). Those in the Duke of Hamilton's Park, are believed to have degenerated in size; & I am informed by Mr. D. Gairdner that the stock kept, in the park of 200 acres, varies from 65 to 80, & that only about 8 or 10 are yearly killed, which seems to show no great fertility.

In the closely analogous case of Fallow Deer in parks, I find that the owners go to the trouble of occasionally import obtaining bucks from other parks to cross the breed. It is be In the case of the aurochs of Lithuania, which have a much wider range than the wild cattle of the British park, some authors believe that they have become considerably reduced in size. So it certainly is (Scrope   ) with the Red Deer of Scotland; but in the latter & indeed in the other cases it seems impossible to decide how much of the decrease of size to attribute to less varied food, & in the case of the Red Deer to sportsmen having picked out for some many generations the finest Bucks; & the less fine having been thus allowed to propagate their kind.*a

(5

(Ch. 3. Good of crossing)

Good effects of crossing. However difficult it may be to obtain quite satisfactory evidence of the ill effects of close interbreeding, the converse of the proposition, namely that good arises as far as increased size, vigour & fertility comes from crossing breeds distinct families & breeds, I think admits of no doubt. I have never met any breeder of animals who doubted it; & it seems useless to adduce authorities or facts. But in regard to plants as varieties have been much more seldom crossed than in animals, I will go into some details to show that the same rule holds with them. (U)

small type

Gærtner, whose accuracy & caution seem to b most trustworthy, believes in the good effect of a taking the pollen from another individual of the same species: he states (Beiträge zur Kenntniss der Befruchtung 1844, s. 366) that he observed this many times, especially in exotic genera, as in Passiflora, Lobelia or Fuchsia.

Herbert (Amaryllidaceæ p 371) says only [text excised]

(6

(Ch. 3. Good of crossing)

same variety or at least from another flower rather than with its own."

[very faint pencil line:] Mr Knight on Peas, Journal Hort Transact vol I was the pollen from same variety or two varieties

Thus far In these cases we have referred to crossing individuals of the same variety; now we come to crosses of distinct varieties.

[6A]

Andrew Knight. (Philosoph. Transact. 1799 p. 200) found that the offspring of crossed varieties of Peas were remarkably tall & vigorous; & that crossed wheat resisted blight better than the pure kinds.

Loudon's Gardeners' Magazine for grapes & other cases (U)

(7

(Ch. 3. good of crossing)

We have seen in crossing individual varieties, that the offspring gains in size, vigour & fertility; in crossing distinct species it would appear that size & vigour is gained in an equal or apparently greater degree, but a fertility is greatly impaired or very often wholly lost. Every traveller has been struck with the health vigour & health of the common mule & this holds good with the hybrid yak in the Himalaya; in the almost almost ster quite sterile hybrid from the fowl & pheasant, in marked increase of size has been often noticed.

In plants every single experimentiser Kolreuter, Gærtner, Sageret, Lecoq Herbert &c have been struck with the wonderful luxuriance height, size vigour, tenacity of life, precocity number of flowers, power of resisting cold &c of most of their Hybrid productions. Kolreuter*(a) (, who is astonished at the portentous size of some of his hybrids & ) gives numerous precise measurements in comparison with both parents. Gærtner*b (…) sums up his conviction on this subject in the strongest manner.

Kölreuter attributed these facts to the sterility of hybrids, by owing, I presume, a sort of compensation, in the same manner that capons, emasculated cats, some breeds of oxen oxen? hares? types? (not seer) by Sir P. Egerton) are larger than th unmutilated male animals males. But Gærtner (p. 394 & 526) has shown that there is much difficulty

8

(Ch. 3. good of crossing)

in admitting this explanation to its full extent; for there is no parallelism between the degree of sterility & amount of the increase of size or luxuriance of growth; indeed most of the most striking cases have been observed in not very sterile hybrids. as shown by the luxuriance &It deserves notice that the The mass luxuriance are enormous size of the roots in a hybrid Mirabilis (*Nova acta 1795 p. 316)in a crossed hybrid Mirabilis of unusual fertility for a hybrid having been found to be was fd to be inherited. inheritable in an individual as hybrid mirabilis of of having unusual fertility. It would seems probable that the effect result is due both to greater growth owing that nutriment as power which would ought to have gone formed sends flowed to the sexual function being applied to general growth, & secondly to that same course general law seem apparently which as we have seen gives to the mongrels from, animals & plants between varieties not only increased fertility but greater constitutional vigour & growth size. without any less, seem apparently with all excess, of fertility. It is not a little remarkable thus to see under such opposite contingencies as increased & decre decreased fertility, an accession of size & vigour. (U)

It is well ascertained (Gærtner Bastarderzeugung p. 430) that hybrids will always breed more easily with one of their parents, than when self fertilised; & indeed not rarely with a third distinct species, than when self-crossed or self-fertilised or crossed inter se. (U) —Herbert would explain even this fact by the advantage of a fresh cross, but Gærtner far more justly accounts for it, by the pollen of the hybrid plant, being in itself in some degree vitiated, whereas the pollen

(9

(Ch. 3. good of crossing)

of either parent species or of a third distinct species is sound. Nevertheless there are some facts on record, which seem to show that even in hybrid a fresh cross does do some good in respect to their fertility. Herbert states (amaryllidaceæ 1837 p. 371 The statement is confirmed by after experiments tried during several years experience in Horticultural Soc. Journal. Vol. 2. p. 19) that he having in flower at same time repea nine very complicated hybrid

[9A]

Now considering how many crossed Hippeastrums were experimentised on, & that they were crossed in all sorts of ways, & that the pollen in each case applied to the stigma, of one plant was from some other hybrid, & therefore not sound, I can understand the strong & (U)

(10

(Ch. 3. good of crossing)

marked overpowering good effect of its application, only on the same principle abstract good from crossing, as seen in crossing varieties. Moreover this case of the hybrid Hippeastrums is confirmed as we shall hereafter see in the chapter on Hybridism by in some degree by some extraordinary cases facts cases, well ascertained by Gærtner, Kolreuter, & Herbert, which will be given in my chapter on Hybridism in which pure species of Lobelia, Passiflora, Hippeastrum, Crinum Hippeastrum Zephycanthes Verbascum, in had both pollen & germ in proper state for they could condition as shown by their fertilising, & being fertilised by, other species, but yet were incapable of, fertilising floret self-fertilisation are when, when their own pollen being was placed on their own stigmas. in same manner These facts seem to show that there is some good

intelligible only on the view that there is some good in crossing, even between distinct

show that in crossing hybrids from distinct species, independently of the greater vigour & luxuriance often acquired, that even in regard to fertility, which is undoubtedly most generally are almost all cases universally greatly diminished or quite annihilated, there is some slight counter-balancing good in the act of crossing which occasionally appears in the intercrossing of of hybrid with hybrid, & even in pure, species or more especially in exotic species which we may suppose are

(11

(Ch. 3. Good from changed conditions)

Good from slight changed conditions.— I think some little light can be thrown on the good resulting from slight crossing the breed, from considering the effects on the individual of slightly changed conditions. It has been a very general belief from ancient times to the present day, in many countries, in India for instance that decided good results from taking the seed, from, tuber or bulb of a plant grown in one kind of soil or situation & planting it in another; the most opposite kinds of soil being chosen, seeds, bulbs tubers &c being often interchanged between residents thus situated. I should have thought less of this belief, if it had been confined to cottagers or common farmers, but I find on enquiring from some whose raises business attend especially to raising seed-corn, & whose success is testified by their obtaining the highest prices in the market, that they find it indispensable to change their seed every few years.—One eminent gentleman in this line has two farms at different heights & on very different soils, so that he is able to exchange his own seed, but even with this advantage, he yet finds it advantageous to purchase occasionally & though having the trust to the statement of others to purchase fresh seed grown on other land.*(a)— Mr. Robson, a practical gardener (Cottage Gardener 1856 p. 186)

11v

with request to seed

Bradley

2 writers in G. Chronicle

Drewitt

with respect to tuber of Potato — belief is almost [curiously] acted on the grt power in Lancashire — Oberlin [illeg] — Robson

Jessieu & Sc luten

belief not confined to such f…… or ga……. sums up Chemical changes,

(Reference to which the belief, which has been made by the so much of the [several words illeg or crossed] of the good demand for any young change whether in the seed seed & lutens engraving send to be &c

slight changes in a plan in above they are given seemed fairly well produced.* considering small size of in kinds of seed, it seems barely credible that the supposed good effect can be due to the seed in one soil some chemical element defines in another soil (xx one night effect that plant after on germinating being fixedto the soil & to exactly the same condition would be the good effect of a change. more glaring than accounts)

It would appear as if life having

It this common belief of good [illeg] from a slight change in [illeg] & plant it probably [illeg] same soil [illeg] on the good effect of crossing & the great effect of being [3 words illeg]

* The Rev. D. Walker in his 'Prize Essay of A Highland Agricult. Soc. vol. 2. p. 200', expresses a strong opinion on this subject. See also Marshall's 'Minutes of Agriculture' Nov. 1775. Mr. Loiseleur Deslongchamps gives in his 'Considerations sur les Céreales 1843. p. 200' gives numerous references on this subject.— (U)

(12

(Ch. 3. good from changed conditions)

in positively states that he has d seen himself decided advantage in the obtaining bulbs of the onion, tubers of potatoes & seed from different soils, & from diff distant parts of England. Oberlin (memoirs of p. 73) attributed in great part the surprising good he did effected amongst the poor of the Vosges in the cultivation of the potato, (the yield having been reduced in between 50 & 60 years from 120–150 to only 30 or 40 bushels in the year 1767) to changing the sets. In the cases of good resulting from the exchanging of seeds, I sh should think it could not be explained on the same chemical principles as in the rotation of crops of different species, both namely by the seed obtaining some chemical element in one soil good for when use with say for wheat not found in sufficient abundance in another other soil also good for wheat for how little small a difference in a single grain could the excess be, & this one grain would have has to produce many influence the whole yield of the plant. Such a chemical view has more probability, & yet but not much I think, when applied to the exchange of tubers of potatoes; but even in this case the slice planted bears but a sam small proportion to the yield of tubers. (U) How far the natural rotation of forest land & even meadows, which seems to be now well established.

(p. 13

(Ch. 3)

so careful an agriculturalist [text excised]

followed some such plan.

As animals are less fixed to one spot & the same conditions it is less easy to get evidence of the good of change. But with invalids, (U)

(14

(Ch. 3. good from changed conditions)

I no medical man doubts of such good being most evident. Small farmers again find their cattle prosper prosper best when they can occasionally change their pasture. It seems very doubtful whether in these cases the good can simply be accounted for by some fresh element in their food, which was before wanting. It would rather appear as if the marvellous & complicated play of affinities & constant change by which life is kept up, was somehow stimulated by almost any sort of slight change in the conditions to which the individual is exposed. Judging from plants, as both those which are useful from the number & quality of their seeds, & those which are useful from their organs of vegetation see seem to be benefitted by a change, we may infer, that as by in the case of crossing, both general luxuriance & fertility are increased.

If the facts here just briefly given can be trusted, I think we can in some degree understand the good of crossing, for the individual with a blended constitution, derived from the union of the pollen & germs of male & female from two varieties, differing in (U)

(15

(Ch. 3)

structure or constitution or even two individuals of different families will be exposed all during its life whatever the conditions of its existence may be, to a somewhat different relation with external things to what either of its simple parents can have been;— for I presume it will be admitted that every part of the structure is related either to the external conditions or to other portions of its own structure.

Considering the various cases now discussed,—obscure as many of the facts are & doubtful the evidence—namely the apparent ill effects of close interbreeding, the good from crossing distinct ind individuals of distinct families or varieties, & even of species within in this latter case with the great exception of fertility, considering what little light is thrown on the subject from the good of changed conditions to the individual, I am should be strongly tempted to believe with Mr. Andrew Knight,* that it was an essential part of the great laws of propagation that occasionally there should be the concourse of two separate individuals in the act of reproduction. But instantly it will occur to everyone that there are very many hermaphrodite organisms, with

[15v]

*Philosophical Transactions 1799. p 202. Mr. Knight argues "that nature intended a sexual intercourse shd take place between neighbouring plants of the same species."—Kolreuter in Mem. de l'Acad. St. Petersbourg vol. 3. p. 197 makes striking similar remarks: I think in Ch Portfolio on "Dichogamy".—

16

(Ch. 3. all organisms crossing)

the two sexes united in one individual. How it may be asked can in such cases two individuals occasionally cross? If two an organism can from the day of its creation go on most strictly interbreeding, that is self-fertilising itself from the day of its creation to its extinction, one may well doubt all the foregoing facts & put them all down to popular prejudices. This subject I do not can hardly believe this. The subject has sufficient importance for us, in relation to crossing of slight varieties being a powerful means of keeping a breed or species true,— in relation to some points in geographical distribution,—perhaps to the extinction of species when become very rare, — & to some other points, that I must discuss it at some little length. (Get Huxley to read over for this)

First for some general considerations, which seem to me to have considerable weight. In land animals, after attending to the subject for several years, I have not been able to find any one case, in which the concourse of two individuals is not requisite;* although yet there are a good many hermaphrodite or bisexual animals

[16v]

* The Acarus mentioned by Owen see t authority.

17

(Ch. 3. all organisms cross)

as land-shells, certain annelids, as earth-worms, land-leeches & planariæ, but these all unite in pairs for propagation. In aquatic animals there are numerous cases of wh bisexual hermaphr animals which can certainly propagate by self-fertilisation;

[For readability, Darwin's horizontal and vertical deletion uncrossed.]

If we consider the nature of the liquor seminis in the structure of bisexual animals in presently to be discussed, it is obvious that in aquatic animals there is a the possibility of a  from a fluid

but in these forms the fluid medium in which they live, & from the fluid nature of the liquor seminis there is a possibility of an occasional cross, as & we shall presently see when we consider that this is favoured by their structure. whereas

In land animals, on the other hand from the nature of the liquid liquor seminis it is obvious there never could be a accidental cross between two individuals, without their close contact or union; & this I suspect that I have failed in finding among land bisexual animals any case, as far as I can find out, is the universal rule in land bisexual animals. This fact is the more striking, when we contrast land animals & land plants; in these latter bisexuality hermaphroditism & self fertilisation is the rule &

(18

(Ch. 3. all organisms cross.)

unisexuality (monœcious & diœcious plants) the exception; but in plants the fertilising element or pollen is not liquid & can easily, as is well known, be carried by animals & through the air from plant individual to individual by insects & the wind.

Secondly, in plants it is known (Gærtner Bastarderzeugung p. 11.) that damp winds & rain is are very injurious to their fertilisation; yet in the vast majority of cases the general rule is that flowers are open & fertilisation takes place sub jove under the open sky. Such cases as the snap-dragon & papilionaceous flowers cannot be considered as exceptions, but but rather as confirming the remark, for though they protect the stigma & anthers from rain, like as do drooping tubular & bell-shaped flowers, yet they are not sealed up, but frequently opened & visited by insects. The few cases in which fertilisation seems appears to take place in really closed flowers will be presently discussed.

I am far from pretending that there may not be some other additional & quite different explanation of the generality of the fact of the fertilisation of plants taking place, exposed to the injurious effects of the climate & to an enormous loss of pollen

(19

(Ch. 3. all organisms cross.)

by the consumption of insects, but yet if an occasional cross with another individual is a law of nature, we have an explanation of these facts.

Thirdly, in animals & plants there are many instances of bisexual hermaphrodite & unisexual species in the same group & even frequently in the same genus; that is, we have the two sexes united in the same individual, or in two separate individuals in organisms, in all other respects very closely allied. Now if in function at least, there be no such thing as in nature, as all an hermaphrodite self fertilising itself throughout its whole existence;—if the only difference be in degree, the bisexual organism hermaphrodite occasionally crossing with another individual, the unisexual at every act of propagation, then the concurrence of bisexual & unisexual organisms in the same groups is less less not surprising, & & does not run counter to all Nature in this case, as in other cases, has not gone jumped per saltum moved per saltum.

(20

(Ch. 3 crossing of all animals possible)

Now for some details showing that in all animals the crossing occasional crossing of two individuals seems to be possible: if it could be demonstrated that the structure of any animal was such at all times such that the access of the liquor seminis from another individual was impossible, we should have the case of near this chapter would be nearly super then the conclusion towards which I am tending that an occasional cross is a law of nature would be proved to be erroneous.—I shall pass over those low animals, the protozoa, barely distinguishable from plants, for I believe true sexual generation has not been observed in them; but the steady progress of knowledge of late years should make us very cautious in assuming that they have not sexes. In the lower plants as mosses & lichens there are many cases of species for long periods & in certain countries districts which have here at most rarely been observed seen to produce fructify, being propagated by generation but which are known in other districts & at other times to follow the ordinary law;*(a) & so it may be with some of the lower animals.

All the vertebrata by are bisexual, except as it would appear some fish of the genus Serranus (Quatrefages. Revue   ) I have not seen the memoir of M.) but from what we know of the habits of fish, an

[20v]

* Silliman's Journal vol. 21. p. 171. many several instances are here given taken from the Transactions of the Linnean Soc. of Bordeaux.—

(21

(Ch. 3 crossing of all animals possible)

occasional cross seems far from improbable. In the enormous Kingdom of true articulata (excluding annelids) all are bisexual unisexual, except the acarus previously alluded to, & the order of Cirripedia. In Cirripedes I have shown that a very few are bis unisexual; & that the fertilisation of some other very few which are hermaphrodite are aided by what I have called complemental males, which are distinct individuals; these few species, therefore, can be crossed. But by a piece of good fortune I met with some monstrous specimens (Monograph on the Cirripedia, published by the Ray Soc. 1854. p. 102.) of a Balanus balanoides, a truly hermaphrodite form, in which the male organs were rudimentary, & the channel absolutely imperforate, nevertheless three of these specimens included developed larvæ; almost proving (without we admit lucina sine concubitu) that the liquor seminis from other individuals had gained access to the open sack of these absolut monstrous individuals.

With respect to In the other two great animal Kingdoms, there are many bisexual hermaphrodite forms; but it deserves notice that during the last twenty 20 or 30 years a surprising number of these lower animals, which were formerly thought to be bisexual hermaphrodite are now known to be unisexual.—Of the bisexual hermaphrodite animals

(22

in these many, as all? the gasteropod? or uniform univalve shells, & marine worms or annelids?? all require the concourse of two individuals. Until lately all acephalous mollusca, or bivalve-shells, were thought to be hermaphrodite, but now many as the common mussel & cockle (von Siebold in Wiegmann's Archiv fur Naturgesch 1837. p. 51) are known to be bis unisexual, & their fertilisation must be is probably effected by the spermatozoa being drawn in by the same ciliary currents by which food is aqu obtained; & this same method could facilitate an occasional cross in the hermaphrodite bivalves. I long thought from the description which I had read that the common oyster was a case of perpetual self-fertilisation, but it now seems as I am informed by Prof. Huxley, from the observation of M. Devaine that the male & female products are matured at different periods

[in margin:] V. Owen & Huxley

[Casimir Joseph Devaine/Davaine (1812-1882)]

(   )

& therefore that the oyster though in structure is an hermaphrodite, in function it i would appear to be bis unisexual. (a) From the analogy of plants, I should expect that this maturity at different periods would prove to be of frequent occurrence with

(22

(a) This I am informed by This likewise, according to Prof. Huxley's is, also own observations is the case with the bisexual hermaphrodite ascidians.

(23

(Ch. 3 all animals cross)

animals. In all cases of aquatic In parasitic worms or Entozoa, some many are bisexual unisexual but some which are hermaphrodite (Dr. Creplin in appendix to Steenstrup's Untersuchungen über das vorkommen des Hermaphroditismus Dr. Hornschuch 1846. A bran I have seen a translation of this owing to the kindness of Mr. Busk) require mutually unite; & Dr. Creplin sa remarks that in those in which von Siebold discovered an internal passage from the male to the female organs, apparently insuring perpetual self-fertilisation, the so-called cirrus exists, which would lead from analogy to the conclusion that there must be likewise at least occasional mutual fertilisation.

Distrusting my own knowledge I applied to Prof. Huxley, whose knowledge of the invertebrate animals is well known to be profound, whether he knew of any animals whose structure was such that an occasional cross was physically impossible. He informs me that some of the jelly-fish (Beroidæ) seem to offer the greatest difficulty, but even in them it is not positively known whether or not the eggs are discharged fertilised;

(24

(Ch. 3 all animals cross)

; that as these animals derive their food from indrawn currents of water, which bathe the ovaria, it is certainly quite possible that the spermatozoa of other individuals might come into action. (a)

Again Prof. Huxley writes to informs me that he should have thought that the bisexual hermaphrodite Bryozoa or Polyzoa (certain corallines) would have offered insuperable difficulties to an occasional cross, had it not been for Mr. Hinck's observations, who saw in some species the spermatozoa pouring out in clouds from pores between the tentacula; & as Prof. Huxley remarks what could this be for, except to fertilise some other individual. Moreover there are some unisexual Polyzoa Bryozoa, with the sexes distinct, (a) which proves that fertilisation can be effected between the separated, & yet fixed polyps.

[Pencil note:] I might put in note x after chap of Polyzoa

In all these cases of aquatic animals it is well remember Spallanzanis (Dissertation II relative to natural History. English Translat.) curious experiment, namely that three grains of the liquor seminis of a frog thoroughly diffused in a

[24v]

Nordman & Owen on sexes separate in Flustra

Hincks Brit Assoc 1852

Proc of Scot p. 75

[24vv]

L' Institut 1839 p 95 – on sexes in coralline allied to Flustra & on zoospermatic animalcules!

(25

(Ch. 3 all animals cross)

pound & a half of water retained its full power, & even that the same quantity when diffused in 22 pounds sufficed to vivify some of the eggs. The weight of the liquor seminis subjove to fertilise a single egg was calculated to be only 1/199,468,7500 of a grain! Finally as far as I can discover, under our present state of knowledge, no animal is known, the structure of which would prevent an occasional cross; & this fact, considering the astounding diversity of nature, seems to me an improbable coincidence, without the capacity of such occasional crossing be one of the laws of propagation reproduction

In Bee v. Siebold shows semen keeps power for 4 or 5 years.

(26

(Ch. 3 all plants cross)

Crossing of Plants. To show that all plants are capable of being occasionally crossed by another individual of the same species, is more difficult than with animals. Bisexuality Hermaphroditism with self-fertilisation is here the rule, & the separation of the sexes the exception.

The mere clos proximity of the male & female organs in the same flower,—the apparent frequency of the pollen & stigma being ready at the same time,—the explosion of the anthers close to the stigma & the lightness of the pollen,—the movement of the stamens to the pistil & of the pistil towards the stamens, seems would all at first lead to the conclusion that self-fertilisation would be almost in variable invariable. But I think we shall see that such a conclusion would be hasty. Besides the comparatively few mono and dioecious monoicous & dioicous plants, C. C. Sprengel* (a) has shown that many hermaphrodite plants are what he calls dichogamous,— that is namely that either the pollen is ready & is is ready & seen mature & has been shed in one flower before its stigma is ready to receive it, or on the contrary (which is a less frequent case) the stigma is ready for fertilisation before the pollen anthers have burst; hence in these first cases, the plants are either essentially bisexual unisexual, being fertilised by either by a the pollen of either an younger older or younger flower or at least an occasional cross is greatly facilitated; I cannot doubt from the observations of others, & even from my own that these cases are frequent.

I may state that I have tested during several years many of Sprengels observations, in those cases in which I could judge by the clefts of the stigma, opening &c, & am convinced of his general accuracy.* [very faint words in pencil:] Cassia not Ch probable Lobelia Admirable

add half-dichogamous

[26v]

* The curious work containing these observations is entitled "Das Entdeckte Geheimniss der Natur 1793." The greatest living Botanist, Robert Brown, thinks highly of Sprengel's power of observation, as I know from conversation have heard from him. I mention this because Gærtner in his two admirable works speaks lightly of does not seem to think much highly of Sprengel; & attributes He gives, however, (Bastarderzeugung p. 65) one strong case of inevitable dichogamy & seems to admits (p. 659) that in many plants, as in whole families, that the pollen and stigma are do not ready come to maturity at the same time, but in many of such them cases it does not appear that the pollen is shed many these cases, probably in most, the pollen is retained close at hand so that it may easily impregnate fertilise the pistil in the same flower. A. F. Wiegmann (Über die Bastardzeugung 1828. s. x) says he has after careful observation he is convinced that most of the obser statements of Sprengel are correct, & that he could write a commentary on his work. I may

(26 bis

(Ch. 3 all plants cross)

It would be useless to give examples of dichogamy from Sprengel; they are so numerous, for instance in my many Scrophulariaceæ, & in all or in most Umbelliferæ; (Das Entdeckte &c p.  28, 154, 50, 322 &); in many Onagraceæ as I have myself observed in genera not noticed by Sprengel. So again Kölreuter observed that long similar facts long ago (Mem. de l'Acad. St. Petersburg. Tom 3. p. 197) in many Malvaceæ.

This seems to be the case from Cassini's observations (quoted in Linn. Transact. vol XIII. p. 595) "nearly throughout the Compositæ."; & the pollen in this great Family was observed by Kölreuter to be aculeate, & specially apt adapted to adhere to insects. In Lobelia, judging from an my own examination of a few species, the pollen is swept clean out of the united anthers, in the same manner as in the Compositæ, by the fri fringe base on the style, some time before the stigma is ready for its reception. That the growth of the pistil —in these cases is really adapted to sweep the pollen out of the anthers, before the stigma is mature, I must think from having observed the same process effected by very different means in a hardy perennial the Crucianella stylosa (?) here the mouth of the corolla is much contracted, so that the anthers, which open whilst the flower is in bud, instead of being united together as in Lobelia & the Compositæ, are pressed close round the pistil. The style is of remarkable length, & lies zig-zag in the bud; as soon as the flower opens it is rather quickly & sometimes suddenly protruded by its elasticity; & in this movement owing to its the largely knobbed & rugose stigma, it pushes out ⸮ ⸮ all its own the pollen no; & not till some time afterward does the stigma open & becoming humid is apparently ready for fertilisation.

(27

(Ch. 3 all plants cross)

general accuracy

It is known that many cultivated varieties of plants, show not only that they are capable of being occasionally crossing, but without great care are actually crossed very frequently. (zz) This as every one knows holds good remarkably with The Cruciferæ are particularly apt to be adulterated, a single cabbage*a plant sufficing to contaminate whole beds of other varieties. I had a radish plant which seeded flowered amongst sever in the same bed with several other varieties: I saved a few seeds from one plant, & out of the 22 plants which I raised had obviously been crossed only 12 came true to their kind. (a) Gallesio in his treatise on oranges does not in the last least doubt that oranges very commonly cross. It is impossible to prevent the different varieties of Rhubarb (as I have known myself) from crossing, if grown near each other. (B) And many other instances in Rhododendron, Berberis, Poppies (in which latter I know of case in which not one seedling came true) could be given (zz)

But by far the strongest proof, as it seems to me, of the extent to which the pollen from one individual flower is carried to th other flowers of the same species is incidentally offered by hybridisers. Every single one all these of these experimentisers, Without a single exception, all these naturalists, several of whom have devoted their lives to the subject, insist in the strongest manner on the absolute necessity of perfect isolation of the castrated pla flower,*(b3) so as to preclude the possibility of access of its own pollen. Herbert (Amaryllidaceæ p. 349) positively states that it is not always sufficient to enclose

insert p. 557 Ch E. (Q)

[27v]

(a) text, So, again, with turnips (Gardeners' Chronicle 1856 p. 729)

In the Cruciferæ according to Gærtner (Bastardzeugung s. 659). the pollen & stigma are not ready at the same time; but I doubt whether this alone will account for the extent Prepotency to which they blend, & I suspect that the pollen of one another variety must have a prepotent power effect over the pollen of the stigma's own flower, in the same way as it is known that the pollen of one species is prepotent over & obliterates the effect of the pollen of another species, previously placed on a stigma.—

(B) text. The various species of Crinum sent by W. Herbert (amaryllidaceæ p. 32) to Calcutta cross so freely in the open air garden, that true seed cannot be saved. Prepotency

[27v]

[pencil line illeg]

(zz) The mere circumstance of great beds of certain one variety being cultivated in any one place is alone a considerable protection that many seeds Prepotency shall not be sayadulterated; & hence The certain villages (Lindley's Horticulture p. 319) have become famous for pure seed of certain [illeg] plant varieties, [3 words illeg] owing to the masses masses of the same variety there cultivated & to the exclusion of other kinds. how much of plant The ill effects facility of adulteration particularly effects (Q)

[27v]

But even in the largest nurseries, it is surprising the trouble which the owners are compelled to take (Prepotency) to keep their seed crops unadulterated; thus Messrs. Sharp "have land engaged in the growth of seed in no less than eight parishes."* (* Gardeners' Chronicle 1856. p. 823).

[27v]

Kolreuter Dritte Fortsetzung. s. 56.

Hybrid Pinks often arise naturally in gardens.

(28

(Ch. 3 all plants cross)

a flower in gauze; so subtle are the means by which pollen can be introduced: from some experiments in hybridising which I have made myself under gauze or [illeg], I suspect that it is the minute insect Thrips which in these cases brings pollen, as I have found that it made could crawls into flowers protected by gauze & which insect I have often & I have often found this insect dusted with pollen. In the first season of Gærtners grand series of observations he crossed many as he believed manyafter castration 20 distinct genera, & obtained, as he thought hybrids from nearly all; but Herbert, who had been in the field before, at once published his entire disbelief of these experiments, & asserted that the isolation had not been sufficient; which was subsequently acknowledged ( Bastardzeugung. s. 128) with perfect candour by Gærtner. Prof. Henschel's experiments, worthless in all other respect (given by Gærtner in his Kentniss s. 574) are interesting as showing the extent to which flowers crossing goes on naturally without they be completely isolated; he castrated flowers of 37 ♂ species (belonging to about 22 genera,) & either did put on no pollen or pollen of other genera &c, & yet obtained seedlings from all.—Other parallel cases from of experiments made by Dr. Mauz might have been given. No doubt in most many of these cases the fertilisation has been effected by pollen carelessly left in the castrated flowers.

But a most curious table published by Gærtner (Kentniss s 550)

(29

(Ch. 3 all plants cross)

shows I think conclusively how to what a wonderful extent pollen is carried from flower to flower. In 1825 he castrated 520 flowers & placed in them pollen of other species & genera; & as he says he thought it laugable to suppose (Kentniss s. 539, & 575) that pollen could be brought to his castrated flowers from other flowers of the same species growing between 500 & 600 yards distant, he did not isolate them the plants more perfectly. The result was (Kentniss s. 576)

270 [+] 19 [=] 289

Flowers

19. Which produced seed that did not germinate, & therefore have no bearing whatever on the experim result, & may be eliminated.

29. which produced true hybrids, & therefore the pollen, intentionally placed on them produced its effect.—

270 which remained unimpregnated, & therefore on which the foreign no pollen was brought had no effect, & on which the pollen of its own kind had not been brought by any agency.

202. produced seed, which yielded pure plants, & therefore on which the foreign pollen had produced no effect, but pollen of its own kind had somehow been introduced.

520 total number of flowers experimentised on in 1825.

Now one's first impression is that in the 202 castrated flowers, impregnated attempted to be impregnated with other pollen, but which produced their own kind, is that their own pollen must have been carelessly left in; but Gærtners tables (Kentniss &c s. 555 & 576) shows that this explanation is not sufficient, for during the 18 subsequent years he experimentised on castrated no less than 8042

(30

(Ch. 3 all plants cross)

flowers, & always did this kept them in a closed room, so that they could not possibly get pollen from other individuals g of the same species, & then during these many years & out of the 8042 flowers he had only 70 cases of seed producing pure plants, showing, that pollen h the castration had been imperfect; whereas in 1825 when he experimentised in the open air we have seen that out of 520 flowers he had 202 cases produced pure flowers seedlings! Yet the plants of the same species in several of the cases did not grow within 500 or 600 yards distance*! It should, however, be not overlooked that when a plant flower is castrated, the stigma retains its facil capacity for fertilisation (Kentniss s. 145) for a considerable time, so that a castrated flower would have a much better chance of being fertilised by pollen from another individual, than would a plant having pollen of its own, the action of which would fertilise the pistil.

Now considering that there are some monœcious & dioicous plants,—that there are many dichogamous plants of C. C. Sprengel, & half semi-dichogamous which are in fact diœcious monœcious or dioicous—considering the many cases of the intercrossing of varieties in our gardens—& especially considering the astonishing care which all hybridisers have found absolutely essential to prevent the pollen of

[30v]

quote under Cabbages

* Wiegmann's experiments (Über die Bastardzeugung s. 32, 33) on cabbages show the extraordinary degree in which they cross without artificial aid. A most intelligent foreman in a nursery garden assured me that he had known seed of a plot of Brussels-sprouts spoiled by a bed of Drum-head cabbages about 200 yards off. Mr. Masters of Canterbury has known a single Red Cabbage spoil the seed of Savoys, Cabbage & Broccoli in neighbouring gardens.—Many other instances could be given.—

* (b) See Gærtners, the most admirable of all observers on this subject, strong expression on this subject in his Bastardzeugung s. 670. Experiments made in the open air, he says, must be absolutely rejected. (Beiträge zur Kenntniss s. 527 510, 573), See also Lecoq De la Fecondation &c. 1845. p. 27.

[30v]

*a Gærtner (Bastardzeugung p. 566) gives an experiment on 4 flowers of plants of Matthiola annua, the flowers Ch E of which he castrated, & kept two in his room unfertilised & they produced no seed; the other two he placed in his garden, 100 yards distant from some other plants; both of them produced some poor pods, containing 68 apparently good seed, of from which, however, only 20 seedlings were raised.

See p. 573 for an analogous fact with Nicotiana.

(31

(Ch. 3 all plants cross)

its own kind being brought to the castrated flowers—& considering the hybridisers have indiscriminately from varied motives worked on nearly all kinds of flowers, (a) I must conclude that the transmission of the pollen from individual to individual is not only very generally possible, but that it actually is so transmitted. Some further facts will also be presently given.

Before considering the many grave case of difficulty opposed to the foregoing conclusion being made universal, it may be interesting briefly to consider the means of transmission.

It is known that in many plants with the sexes in separate flowers but certainly not in all, the pollen is brought carried by the wind, & hence pollen has to be produced in such astonishing quantities, that many buckets full of the pollen of various fir-trees that is have been swept off the decks of ships by mainly by buckets full on the shores of N. America. (Silliman's Journal Jan. 1842). In some associated plants hermaphrodite plants, as in Gramineæ, in which the stigma is large, branched & at the period of fertilisation for a time fully exposed, in which the pollen is but

But in most bisexual hermaphrodite flowers, owing to their structure, or to the small quantity of the pollen, or to its coherence & or to the small size of the stigma, I think it may safely be concluded that the wind can but seldom bring sufficient pollen (for several grains are almost always required for the act of fertilisation) from one flower to the other so as to effect a cross between two individuals. Their hav

[31v]

—lastly considering the many cases, in our gardens & in a state of nature, of hybrids spontaneously air being formed—

(32

(Ch. 3 all plants cross)

little coherent, & the long slender filaments seem formed to scatter the pollen, I do not doubt that crosses must be often effected by the wind. Glycine fluid

Insects of various orders, more especially Bees,*zz are the great agents. Many flowers cannot be fertilised without their agency, as is admitted, though very unwillingly, by Gærtner. (Beiträge zur Kentniss. s. 335) it is impossible to read C. C. Sprengels details & then examine many flowers, as most Irideæ, Passiflora, Viola &, most Orchideæ &c &c or many orchideæ & in regard to many & & doubt this: in regard to many Orchideæ R. Brown says th all the Ascelpiadeæ which have been carefully examined, Robert Brown, says the "absolute necessity" of the assistance of insects is manifest, (Linnean Transact. vol 16. p. 731) & Gærtner Sprengel So again Ch. Morren. believes that their agency is rendered more effectual by their staggering movements, extraordinary activity, owing due to the intoxicating effect of the nectar.—It would be tedious to give other examples. All those who have personally attended to the subject have become strongly impressed with the efficiency of insect agency in the fertilisation of flowers.* So again Ch. Morren.

(32v]

*zz. Bees are found in every region all parts of the world; even in the extreme Arctic regions they have been seen (   ) sucking the flowers. But I must add that on the little coral-islets, called the Keeling Islands, in the Indian Ocean, I found no Bees; but there were other insects.

[32a]

* p. 32. Ch. 3) Note)

M.S chapter on Intercrossing Habit of Bees

I think I ought to look over whole M.S. Chapter note not in

There can be little doubt that C. C. Sprengel has pushed his ideas views to a quite fanciful degree; when as for instance, when he accounts for all the streaks of colour on the petals, as formed serving to guide insects to the nectary.

It is almost superfluous, but he says state that

Yet somehow I have observed instances quite opp

Although I have seen quite enough to convince me that this charge is quite fanciful yet Nevertheless some facts could be given to in favour of it such a view: (Thus I in a patch of the little blue Lobelia, which was incessantly visited by Hive Bees, I found that the flowers from which if the corolla, or the lower streaked petal was alone had been cut off, were no longer visited. Whether the Bees were then led to think that these flowers were withered, or whether the absence of this convenient alighting place on the lower petal was the cause, I know not. But I feel sure that Bees work seem to work against each other with excessive industry competition, so that they grudge the least loss of time: thus when visiting flowers with several nectaries if one be dry, they do not try the others; again when visiting flowers which have been bored, when they if one had has accidentally not been bored I have seen Bee after Bee pass over it crawling over on the mouth & not stop to bite a hole nor will they enter the open tubular flower, though having to crawl over it, but will dash on to another bored flower. By the way, if proof were wanted how little Bees require any guide to the nectary, their habit of bor biting holes in the lower part of the corolla or through the calyx, so as to reach the nectary without the the loss of time of crawling in at the mouth of the flower would prove it. Although These holes when once formed are known to & used by Bees

[32bv]

Note continued to p. 32 Ch. 3)

of various species & genera: when as in Kidney beans, the hole has been bored on the lower & li side of the calyx, bee after bee flies to the under side with unerring precision. Bees, as far as I can judge are guided by various senses to flowers, & more especially by knowledge of the position of each tuft of flowers in a garden. It is well known that the same Bee keeps as long much as it can to the same species, when getting nectar; & I have repeatedly seen them flying round a room in a direct line clearly determined course from plant to plant of the same species, when round a corner & so out of sight.—They most strikingly opposite are good Botanists, & know well that plants varieties plants of the same species may have m brilliantly different colours; but they know that they are only varieties & visit them indiscriminately. I think they recognise a plant by its general habit; I have seen Humble bees after visiting a tall blue Larkspur fly to another plant, of which the buds were so little open, that they were hardly tinged with blue. They seem often to be aware if another Bee has almost instantly before visited a flower, & will then not try; but I have seen one blunder & itself visit the same flower twice.

(33

(Ch. 3 all plants cross)

It is, I think, impossible to doubt that the structure of very many flowers has been formed in direct relation to the part which insects play in their fertilisation. What can be a more beautiful adaptation than that shown by R. Brown to exist in the Asclepiadeæ & Orchideæ, between the stickiness of the gland of the pollen masses, of their separate grains one to another & to the surface of the stigma, by which it follows that the instant an insect touches the gland it draws out the whole pollen mass out of its case, & then as it crawls over the sticky stigmas its surfa of the several flowers, as the insect crawls from one to ano the other, each take a few grains of pollen from the coherent mass. It is worth anyones white while to watch a Bee visiting a Salvia, or to push some thin body like the Bees head down the tube of this flower, & notice how the anthers & stigma are protruded & rubbed on the Bee's back; or on the then let him cut open the flower & see the cause of this is two projections at near the base of the stamens, closing the passage, & the movements of which by the

(34

(Ch. 3 all plants cross)

Bees proboscis, causes the exsertion protrusion of the anthers & stigma from beneath their hood: I can no more doubt the final cause of this structure than I can of a certain mouse-traps. I have seen in a Mimulus a Bee enter the flower of a Mimulus & in doing this the two-lipped stigma fairly licked the back of the insect which was thickly dusted with the pollen from another flower, & then the two lips of the stigma slowly closed on the pollen which it had thus obtained. It is pretty to compare the mere power different of movements being moved by in the part of the flower in those species of Fumaria, in which either one or both nectaries secrete honey, the different power movements of the parts of the flower as a Bee enters.

Even in trifling details as in the position of the anthers stamens & pistil, in relation to the nectary, I believe that there is very often generally a distinct relation to the action made action of insects: thus in the Dictamnus Fraxinella, I noticed during several days that the stamens & pistil were placed so that a Bee visiting the nectary would not touch them; but then came a hot day & the anthers all burst & stigma was humid, & I found their positions all changed & they were now fixed their tips now stood in the direct gangway to the nectary, & were

(35

(Ch. 3 all plants cross)

brushed by every Bee which entered. I could fill pages full of other instances from C. C. Sprengel & seen from my own observations.) (I will only allude to the case of the Berberis (B)

(Bees & other insects visit flowers both for the pollen & nectar. The nectar cannot be supposed to be formed, any more than the pollen, for the sole purpose of attracting insects; for nectar is sometimes secreted sometimes in outside flowers, as by the bracts of various Leguminosæ (I called attention to this fact in the Gardeners' Chronicle, 1855 July 21st, & had at that time quite forgotten that it had been previously noticed by Sprengel), but nature has utilised this secretion for the very distinct purpose of facilitating fertilisation, & as I believe occasional crossing) For

When Kolreuter first discovered (Vorlaufige Nachricht 1761 p. 22) that the Malvaceæ, owing to the adhesive pollen & stigma not being ready at the same time in the same flower, can be fertilised only by the agency of insects, he says he was astonished that so important a function should have been left, as he then thought to accident,—to a mere happy chance; but he adds that further observation convinced him that the wise Creator has thus used the most

[35v]

zz text to page at back of p. 35

Thus in regard to the pistil of a Goldfussia, it is scarcely possible to doubt from Ch. Morrens (Nouv. Mém. de l'Acad. Roy. de Bruxelles. Tom XII 1839.1) remarks & curious observations that the movement of the stigma when touched towards the lower side of the corolla, where the fallen pollen is collected, stands in direct relation to the action of insects. Again in Stylidium, as described by Ch. Morren (Ib. Tom XI. 1838) I can see no difficulty, from the proportions in the parts, of a Bee carrying pollen from flowers, when by sucking at the nectary it causes the sudden & remarkable movement of the column; though Ch. Morren may be quite correct that this movement, also, aids the fertilisation of the flower by its own pollen.—

[35v]

B text p. 35

in which the stamens move to the pistil, & in which consequently, it might have been thought there would be seldom any chance of a cross with another individual: but Kolreuter has shown (Nova Acta Petrop. 1788 p. 214) that they never move till touched by some insect; so that insects are necessary to their fertilisation; & as insect their flying from flower to flower could hardly fail to bring pollen from individual to individual. Indeed in the extent to which the American evergreen Barberries (Mahonia) have been hybridised together, so that it is almost difficult in our nursery gardens, as I have seen found, to get a pure plant, shows that this in the has occurred not only with the individuals of the same species, but of different species. Similar remarks are applicable to some other plants, of which either the stamen of which or pistils move on being touched. (zz text)*)

*In Parnassia palustris the stamens slowly move one after the other over the pistil; but Sprengel (Geheimniss &c 167) positively asserts that the pistil at this period is not fit for fertilisation, & therefore that the plant is strictly dichogamous he supposes that it is fertilised by pollen from a younger flower brought by some nocturnal insect. Allium p (ib. p. 186) is in nearly the same case.

(36

(Ch. 3 all plants cross) Diptera

sure means. Hardly any means, I am convinced, could be surer; Besides bees, I have seen numerous small beetles, dusted with pollen fly from flower to flower & in regard to our present discussion, it should be borne in mind that in every case in which insect agency is essential to their fertilisation, & indeed in every case in which insects habitually visit flowers during this period, it is hardly possible to doubt that pollen is often brought from flower to flower of distinct individuals, & thus a cross between separate individuals of the same species effected. I have repeatedly seen many minute beetles, dusted with pollen, fly from flower to flower: some flowers, which are hardly very rarely visited by bees as the Phloxes (which I have never seen visited except during one year) are frequently visited by butterflies: [text excised]

[36v]

I have remarked this particularly with the Rhingia rostrata on the Lychnis dioica, on an Ajuga & on many others, I have seen the same thing with Volucella plumosa on a Myosotis,—I may add that I have never seen a Bee visiting a Daisy but I have seen the Rhingia, Scæva iris (?) & Hilara globulipes all thickly dusted with the pollen of this plant

(37

(Ch. 3 all plants cross)

flight, dusted like millers with pollen. I have seen several times the same thing with the Thrips, an insect hardly larger than a bit of chopped horse hair bristle: one day I noticed one watched with a lens, one in the flower of a convovulus with having four grains of pollen on its head, & these I saw left on the haired stigma, as it crawled over it. The crossing of the great flowers of foreign lands, may be well be aided by Humming & other birds: I remember shooting in S. America, a mocking thrush, which had its head of so bright an orange from the pollen of a Cassia that I at first thought it was a new species.—

But Bees are the most important of all insects for this end. Until I watched I was not at all aware how quickly they work. In exactly one minute I saw one Humble-Bee visit 24 of the closed flowers of a small toad-flax (Linaria cymbalaria); another 22 flowers of the Snow-berry tree (Chiococca Symphoricarpos racemosa); another be very long[2 pencil words illeg]17 flowers of a Larkspur on two separate plants &c.— The leading top flower of an Oenothera was visited eight times by Humble Bees in 15 minutes (a) (a) in 19 minutes each flower of a tuft of Nemophila insignis was visited twice: by Bee in a large plant of Dictamnus Fraxinella with 280 flowers, on from the rate at which Bees visited it, as observed during

[37v]

& I noticed that one Bee visited in the course of a few minutes every single plant of Oenothera in a large flower garden; passing over, without regard, other plants having large yellow flowers, like Escholtzia:

(38

(Ch. 3 all plants cross) (Flower long span

several days, each flower at lowest computation must have been visited daily 30 times, but 40. It is no wonder that the beauty of many flowers, as I have noticed in some Mimuli & Lathyrus grandiflora, is greatly destroyed by the scr scratching of the feet hooked tarsi of the bees. Some flowers seem never visited by Bees; but with the exception of the Gramineæ in all other cases of indigenous plants to which I have attended I have found other insects that they were visited by other insects.

In Night-blooming flowers, which are often sweet-scented & of a white colour, I have reason to believe are visited by in moths. Much so One must be very cautious before assuming that any any flower is not visited by Bees: in the first summer of my observations on this subject I watched many times daily for 14 days the Linaria cymbalaria & never saw a Bee look at a flower it, when suddenly after a hot day Hive Bees swarmed were most industriously at work.

So again for a fortnight I saw Bees visiting White & Red clovers, but never looking at the little yellow ⸮ Trifolium minus; not & as the flowers were so minute I doubted whether they would ever visit them; when suddenly I one day found innumerable bees hard at work at this species over the whole country, & neglecting the other kinds. In all these most cases as far as I could judge believe that the secretion of the nectar, which determines the visits of the Bees is coincident

39)

(Ch. 3 all plants cross)

Pollen covered from [flower] to [flower]

with the flowers being ready for fertilisation. The secretion of the nectar seems in close relation to temperature: I have observed in a little blue Lobelia, that if the sun went behind a cloud for even half an hour, the visits of the Bees immediately slackened & soon ceased.*

(see [illeg])

(40

(Ch. 3. all plants cross)

surprised at this, seeing how much Thyme is frequented by Bees & flies.*— on the other hand I examined a a I found a hybrid Rhododendron which quite destitute of pollen, & which was very so seldom visited by Bees, so seldom that after long watching the bees for many days I never saw but four Bees visit it: yet on one morning I found from 50 to 100 grains of pollen of Azalea or Rhododendron on the stigmas of these flowers: another day I examined the stigmas of 19 flowers & on 13 of them I found some there was the same pollen. Kölreuter relates (Fortsetzung &c 1763 p. 69) a curious experiment bearing on this subject: in an Hibiscus, which is necessarily fertilised by insects, because its pollen is shed before the stigmas are ready, he took marked 310 flowers & artificially brought by a enamel hair brush daily put pollen on their stigmas for more than a month every day, so that they cd not have been [2 words illeg]; he & left the same number of other flowers to the agency of insects which did not work during some days but as the weather was [illeg], for some days was cold with continued rain. He then counted the seeds of both lots; the flowers which he fertilised with such astonishing care produced 11,237 seeds & those left to the insects 10,886—that is only 351 more fewer seeds.

[Pencil note:] This had better come in Chapter of frequency of & visit of insects—

My case of Holly in origin

[40A]

In a flower garden withcontaining some plants of Oenothera, the pollen of which can easily be recognised from its great size & shape, I was surprised to notice as to how found not only single grains, but whole masses of this pollen, & within many flowers, asof Mimulus, Digitalis, Antirrhinum, & Linaria. The bees had carried Other kinds of pollen were likewise distributed within flowers I likewise examined the stigma & likewise of some other kinds, which I could was able to recognise.

From a Linaria I gathered by chance three little flower branches & in each on five of three to five flowers and on each of them, in & in from three to five flowers of each of their branches, I found the se pollen of the Oenothera. This led me to notice carefully during several days a large number of the stigmas of a plant of Thyme (Thymus vulgaris) in which the stamens anthers were completely aborted & without a grain of pollen; I cut off three were like examined & three stigmas, though scarcely larger than a divided split needle, & examined them under the microscope; all except two were actually covered not only with, the pollen of Thyme brought by the bees from other plants, as the garden, min mingled but with several other kinds, of pollen.) of pollen: but I was not

[40v]

* Those who have not attended to the subject of Hybridism; may feel inclined to exclaim that if pollen is carried from distinct species to species, so freely as these facts show in the cases, an endless number of hybrids would be formed.

But nature has provided a most efficient check to this, namely in the prepotent effect of each species own pollen; so that all effect from the pollen of another species is obliterated by the previous or subsequent action of its own.—

(41

(Ch. 3. all plants cross)

From the facts now given, at too great length, though I could have given many more, I think it can hardly be doubted that insects play a very important part in the fertilisation of flowers; & furthermore that in those cases in which their agency may be not at all necessary, yet that they can hardly fail occasionally to bring pollen from one individual to another. Nor must the action of the wind be quite overlooked, which may be probably is highly efficient for an occasional cross in some hermaphrodite flowers, as it undoubtedly is in some mono-œcious & dioecious plants for their ordinary fertilisation. I should, indeed, have been inclined boldly to affirm the proposition that all plants are not only capable, but do actually receive an occasional cross, had it not been for the following cases of serious difficulty.

Facts opposed to the doctrine that all in plants an occasional cross is necessary. Very many statements may be found in the works of Botanists not only that the certain plants are fertilised pollen is often matured & shed the anthers burst it before the bud is opened, & therefore when it is physically impossible that there ever could be a cross. which admits of no doubt, but that in certain plants the stigma is regularly fertilised in the unopened flowers.* which would render an occasional cross a physical impossibility. But there are many difficulties in the way of

[41v]

*Thus Aug. de Saint. Hilaire in his admirable Lecons de Bo Tanique 1841. p. 572 says, without entering in details, "Chez une foule de plantes c'est dans le bouton ….que la fecondation s'opère."

(42

(Ch. 3. all plants cross) Difficulties)

ascertaining this; & observations made on only one or on a few flowers during one season cannot avail much; for Gærtner has shown (Beiträge &c. s. 104) that the bursting of the anthers & relative maturity of the stigmas depends much on the weather & varies in the same species; & there seems to be no doubt that a plant may be occasionally fertilised in the unopened bud, of which admirably the pollen is ordinarily ready only when the flower is fully expanded. Again Gærtner has shown (Beiträge zur Kenntniss &c. s. 571) that an abnormal precocity not rarely affects many flowers & that in this abnormal state it can be fertilised in the bud. But Gærtner was a strong firm believer that in many plants, even in whole Families, (Bastardzeugung s. 655) as the Leguminosæ, Cruciferæ, Onagraceæ, Campanulaceæ &c, fertilisation takes place, not only some hours, but even from one to two days before the corolla opens. Now I am quite unable to reconcile this statement with others: of the Leguminosæ I shall speak afterwards: of in regard to the Campanulaceæ there has been much discussion on this very point, & notwithstanding Gærtner's statement (Beiträge s. 338) that the stigma can be fertilised at before the clefts are fully marked, I can hardly doubt that Sprengel formerly & Wilson lately (Hookers     ) are correct

(43

(Ch. 3. all plants cross) difficulties)

in believing that the fertilisation takes place after the flower is fully opened; if this be not so Gærtner is correct that the fertilisation takes place in the bud there is the most astonishing an inconceivable waste of pollen on the curiously organised, & retractile collecting hairs of the pistil; & the manner in which Bees, as I have often watched, some frequent the flowers is admirably adapted to bring the pollen from the collecting hairs of the same one or other in flower on to the stigma of another. (zz) So again in regard to the Onagraceæ, I must think the weightiest evidence would be required to overthrow Sprengels statements (Das Entdeckte &c s. 225) in regard to Epilobium & Oenothera (which as far I can judge same from repeated observation seem strictly true) that that far from being fertilised in the bud, they are dichogamous, & invariably fertilised by the pollen of younger, which he saw effected by Humble Bees: Gærtner himself, elsewhere (Beiträge &c s. 104) admits that in some Fuchsias, the pollen is not shed for some days after the flower is fully expanded, as is well known to Hybridisers.* (Lecoq de la Fecondation &c. p. 129)

Lastly with respect to the Cruciferæ, Gærtner's statement that they are fertilised in the bud seems to me quite extraordinary, considering the everyday experience of gardeners with cabbages, turnips, Radishes, &c. Gærtner own experience & to my mind throws doubt on

[43v]

(zz) In Phyteuma, one of the Campanulaceæ, Sprengel says found (Entdeckte s. 117)

plenty of the coloured pollen on the open stigma; but if a branch, with unopened flowers brought with was put into a glass of water in a room where there were no insects, not a grain could be discovered on the stigmas. which had subsequently opened.

(44

(Ch. 3. all plants cross) Difficulties)

his other statements in regard to habitual fertilisation in the bud.)

M. Loiseleur-Deslongchamps (Consid. sur les Céréales 1842. p. 80) believes, though confessedly on imperfect observations & in opposition to some other authors that Wheat is fertilised within the closed flowers. This surprises me much, for by others I have repeatedly seen the florets widely open, with the feathery stigma protruded on one side, with the dangling anthers not fully discharged, & with the grains of pollen sticking over all parts of the florets: in most grasses, all the florets open at the same time & with the protruded stigma, the species plant for the time, as every one must have observed has a very different appearance: in the wheat each floret opens separately & keeps open as very few for only 3, 4 or or 4 hours, leaving the anthers empty anthers dangling outside so that the whole phenomenon is far less conspicuous than in most grasses; & if the Chinese are at all to be trusted some varieties as Huc states flower in the night. The structure is such that I can hardly understand how an occasional cross from another individual can be avoided. A. Knight (Philosophical Transactions 1799. p 200) asserts that by sowing different varieties together,

(45

(Ch. 3. all plants cross) difficulties

"I obtained as many varieties as I wished." Col Le Couteur whose great experience makes his opinion valuable, though he gives no precise facts believes (on the varieties of Wheat, p. 66 &c) that wheats cross. Puvis (De la Dégénération 1837. p. 77) asserts that th nearly all the varieties which were grown near each other in an Agricultural Garden under his charge were each year modified; but his evidence seems to me of little value, as he attributes to the action of the pollen on the grain itself that kind of change which it is known can be results from climate & culture.—Opposed to these statements we have a much more precise one from M. Loiseleur Deslongchamps. (Ib. p. 81) namely that during eight years he cultivated from 100 to 200 varieties very near each other, & that he never saw a hybrid appear. Making some allowance for different varieties, as rem noted in this very respect by Col. Le Couteur, flowering at different var times, & even from the positions of the beds with respect to the wind, this statement is very remarkable, & at first seems almost conclusive against occasional crosses. But I do not think the experiment has been fairly tried, until the different varieties are sown close together, as Knight sowed

(46

(Ch. 3. all plants cross) difficulties)

them; for wheat is not, as far as I can observe visited by insects & a cross could take place only by the wind, & as the pollen is most though pretty plentiful bears no sort of comparison, to the quantity in most those diœcious plants, when in which the wind is the age fertilising agent, crosses could very rarely, perhaps even as several grains of pollen are probably required, take place without the two individual grew quite close together. This remark is probably applicable to most Gramineæ; but the social habits of most of the species in the Family makes the difficulty of an occasional cross less than it would be in other cases less social plants.*

It may, perhaps, be objected, that large trees with thousands or tens of thousands of flowers, (like a large bed of the same variety of a plant in a garden with respect to another variety) could hardly ever fert be crossed from another with the pollen of another distinct individual;—that crossing between the several flowers on the same tree at best would be like the crossing of near relations in animals,— & this, I think is a valid objection. But on the other hand it is a curious fact, which I have heard remarked on by Botanists, & which will strike that if any one if as be will turn over an a Synopsis of the Vegetable Kingdom

[46v]

* Water plants are very apt, I think, in proportion to their numbers, to have their sexes be monoicous or dioicous have their sexes in separate flowers: these, also, are very social plants, as remarked by M. Alph. De Candolle. According to all analogy, the division of labour, or in this instance separation of sexes, is advantageous to all living beings, & therefore it may be that water plants can have this safely partake of this advantage, because they grow nearer each other, & therefore can be more easily fertilised by pollen brought by the wind or insects.—

(47

(Ch. 3. all plants cross, difficulties)

on the Linnean system, he will find that in the Monœcious, & Diœcious, & Polygamous classes include a surprising number of trees,—that is that trees are apt to have their sexes separated. by sec Now it is obvious that in flowers, which cannot be fertilised only by the pollen from another flower, there will be a better chance, (whether the pollen be habitually brought by wind or insects) that pollen should be brought from a quite distinct individual, than in the case of a hermaphrodite flower having its own pollen at close at hand.— (a) Moreover trees are very apt to grow together or to be social as may be inferred from the much greater frequency of densely forest-clad-land, than of single scattered trees: This fact relation of sociability may be not be so fa accidental a relation fanciful as it at first seems:—single trees would interbreed & would produce offspring seedlings not so well able to struggle with surrounding vegetation, as the crossed offspring of the same species, & therefore the species might be able to exist,take root & grow only where many several individuals could exist existed. I am aware that there are very numerous exceptions to the above remark that trees have their sexes in separate flowers; when we come to treat of the Leguminosæ with papilo but yet the above coincidence of trees being so often mono or dioicous seems worthy of under our present point of view seems just worth notice.

[very faint pencil line:] (wd it be worth while to tabulate the selec plants)

[47v]

Let any one run over in his mind the trees even in our own small island, & he will find many in this predicament; & even some that are not hermaphrodite, I have reason to believe are according to Sprengel dichogamous.

(47 bis

Subularia one of the strongest cases Sir J. E Smith & others, I long thought a case of stem self support

Babington

like Limosella—

Menyanthes

Podostemon.—

Zostera. Lindley Veg. Kingdom.

(47 bis

(Ch. 3. all plants cross, difficulties)

Some water plants seem to flower always under water with their corolla perfectly closed: if this could be shown to be invariably the case in any species, it would demonstrate that a cross with another individual could never take place. All British Botanists describe the rare Subularia aquatica as flowering under water with the corolla perfectly closed: Prof. Dickie is the only Botanist, whom I know to have examined it often, & he says informs me that he has invariably found it near Aberdeen submerged, with the corolla closed, with fully developed anthers & plenty of seed in autumn: but in Germany Koch (Synopsis Floræ Germ. Edit. 2. p. 73. I am indebted for this reference both to Mr Babington & to Mr H. C. Watson) expressly states that 'sub aqua clandestine floret, extra aquam flores parvi albi explicantur.'—

The same thing happens with several other marsh plants; thus Limosella aquatica which in this country generally flowers in the open air, was seen by Dr. Hooker in Kerguelen land flowering with closed corolla under the ice.—The Men Menyanthes trifoliata is hardly a parallel case, for it is not said to flower under water, but on account of the very humid situations in which it grows, it has been asserted (M. Gillibert. Act. Acad. St. Petersburg. 1777. p. 45.)

(47 trés

(Ch. 3. all plants cross, difficulties)

to shed in Russia its pollen & be fertilised with the flower closed; but in Staffordshire I found that this was by no means the case. A more curious case instance is offered by Podostemon, some species of which Dr. Hooker* (Himalayan Journal vol. 2. p. 314) informs me flower under water with their corollas closed, adpressed to coating carpeting the rocky beds of the rapid torrents of the Khasia mountains in Bengal. The species referred to are annual, & appear only in the rainy season when the torrents are swollen, & Dr. Hooker has never seen them flowering in the open air; but he will not assert that this may not sometimes occur, when the torrents sink. Some Podostemaceous Family species of the raise their caulescent stems above water, when they flower; & some few species are monoicous or dioicous, & it is not known whether the latter pollen in these latter species is carried under water from flower to flower, or whether they are fertilised above water. So that, perhaps, this case is not so until the natural history of the Family is more thoroughily worked out, this case is not quite so fatal to the views here advocated as it at first appears. There are several other water plants, belonging to the Naiadaceæ & allied Families,

(47 (4)

(Ch. 3. all plants cross difficulties)

which seem to offer much difficulty to an occasional cross; but in most of them, the manner of fertilisation is are imperfectly known, & several of them are monoicous or dioicous, & therefore it would seem that there must be some means of conveying the pollen under water, from flower to flower.* (This is the conclusion of P. Cavolini in regard to Zostera oceanica, & of Willdenow in regard to Najas &c., see Annals of Botany vol. 2. p. 43. 1806.—The It seems to be now made out that Ruppia maritima rises to the surface to flower.—)

(47 (a

(a) To be inserted in p. 47) Ch Introduction

Put as intro to Trees

To test the foregoing remark a little further, I find that in Great Britain there are 32 indigenous trees;* but I include only half a dozen willows (*I have taken the 4th Edit, of the London Catalogue as my guide for the indigenous trees, & Loudon's Encyclop. to settle what to consider distinguish trees from bushes.—) of these 19 or more than half (5.93) have their sexes separated,—an very large enormous proportion compared with the rest remainder of the British Flora: nor is this wholly owing to any a chance coincidence in some one Family having many trees & now [illeg] & not being hermaphrodite; & having a tendency to separated sexes: for the 32 trees belong to nine Families, & the trees with separate sexes belong to five Families. This result, as far as the number of species of trees with separated sexes would have been greater had I included all the tall dioicous willows, but so that but I have counted only half-a-dozen willows in the 3 thirty-two.

Dr Asa Gray

Remembering that Dr. Hooker* (*Introduction to the Flora of New Zealand. p. xxviii) had observed that the very peculiar Flora of New Zealand was characterised by the number of its trees, & by the number of the plants with more or less separated sexes; I thought the foregoing relation might here be thus well tested: hence I applied to Dr. Hooker, who, not remembering his former results, has go & as this

(47 b

(addition to p 47)

subject is open to doubt under several points of view, has gone over his materials & thinks the following a fair result. There are about 756 phanerogamous plants; & of them no less than 108 are trees. belong to 38 from Of the 108, fifty-two or very nearly half, belong the 18 from have the sexes separated: of shrubs, there are 149, & of these 61 or less considerably less than a third have the sexes separated:— belong of herbaceous plants there are 500, & of these only 121, or nearly not one-fourth have sexes separated. So that we have here the same relation as in Great Britain, with Shrubs shown to be in an intermediate condition. In this case, also, the trees are not confined to some one or two Families, which chanced to have their sexes separated, for they these 108 trees belong to no less than 38 Families, & the 52 trees with sexes separated belong to exactly to 18 Families, or exactly half. Whether or not, in the above record the trees which have not their sexes separated may be dichogamous in C. C. Sprengels sense, I do not here consider.

[47a]

Tree & disformed species p 387

[Letter from Asa Gray, not transcribed]

[47av]

[Letter from Asa Gray, not transcribed]

[47b]

[Letter from Asa Gray, not transcribed]

[47bv]

[Letter from Asa Gray, not transcribed]

(48

(Ch. 3. all plants cross) difficulties)

The following appears a strong case against my doctrine:

M. Auguste Saint-Hilaire (Lecons de Botanique p. 572) states that in Goodenia the pollen is shed in the bud, & then becomes enclosed in a cup surrounding the stigma & is then hermetically sealed; so that here a cross would appear physically impossible. But I observe that R. Brown (Appendix to Flinders Voyage p.  ) speaks of the cup enclosing the pollen till the stigma is ready. & Ch. Morren (Nouveax Mem. de l'Acad. Roy. de Bruxelles Tom XI. 1838 p. 4) speaks of the cup as being excitable, & thus 'qui se ferme apres avoir recu quelques grains de pollen;' therefore I infer it may open itself again— From the analogy with the two Families As the cup seems to be analogous with the collecting hairs in the Campanulaceæ & Lobeliaceæ (to which thes Families the Goodenia is allied) one must much doubt whether the pollen can be cup would act in so opposite a manner as the collecting hairs.

(49

(Ch. 3. all plants cross- difficulties)

The following is a somewhat different case: Fabricius & Sprengel (Das Entdeckte &c. p. 418) have shown that Flies are necessary for the fertilisation of Aristolochia clematitis; but they believe, that when a Fly once enters the tubular flower, it is imprisoned for life by the thick set hairs of on the inside of the corolla: if this be so a cross with another individual could never be effected. But having been myself deceived in a somewhat parallel case I am sceptical on this subject: In in the common Arum maculatum, I found in some flowers from 30 to 60 very midges & minute Flies Diptera of three species, & as many were lying dead at the bottom, & as the filaments on the spadix above the anthers seemed to offer some difficulty to their escape, I concluded that when they fin after once entering a flower they probably never escaped left it. To try this I quietly tied gauze over a flower & came back in on two an hour's time, when I found that several had crawled out of the flower spathe & were in the gauze: I then gathered a flower & breathed hard into it several times, soon several very minute Flies came crawled out

(50

(Ch. 3 all plants cross; difficulties) (5)

Keep MS or [Folio]

dusted all over, even to their wings, with pollen, & flew away; Three of them I distinctly saw fly to another arum about a yard off; they alighted on the, inner lower surface of the spathe & then suddenly flew down down into the flower which I opened this flower & found that although not a single anther was had burst, several grains of arum pollen were lying but at the bottom. of the spathe, near to but not on the stigmas, I found a few grains of pollen, which must unquestionably These must have been brought by the above these Diptera or some other midges minute Diptera minute though they were, from another individual arum plant. I may mention that in some other arums In another flower which I opened had their anthers burst I saw these midges little flies were crawling over the stigmas about & I saw them leave pollen on these stigmas.) in other flowers in which th was th no insect.

I have given all the facts, which I have been able to collect, which seem to be opposed to the doctrine of occasional crossing in more detail, than those which seem to favour it. And there still remain, three cases, viz Hollyocks, certain Orchidaceæ & the Leguminosæ.

(Hollyocks (Alcea). Loudon, Herbert & others have stated that the several differently coloured varieties come true from seed. As from the observation of Kölreuter & Sprengel there can be no doubt that the stigmata)

(51

(Ch. 3. all plants cross. difficulties)

are fertilised by the coherent pollen of younger flowers, by the agency of Bees, which I have actually witnessed myself in a carefully castrated flower; so this true asserted trueness of the many varieties seemed to me very surprising. Hence I f brought 18 packets of the best German seed, & raised 18 little beds of plants; but though generally very true, there were seven beds with one or more plants false; altogether out 111 plants 85 came up quite true & 26 not true to their colour.

Now if the seed-beds were, as is probable, large, this an & if then so that from which it would follow that generally each flower would get have pollen brought to it from the same variety, there is nothing in this proportion to render my doctrine as cast (even if we attribute, as we ought, part some of the false plants to variability,) as ought to to cast doubt on the crossing of Hollyocks.

(52

(Ch. 3. all plants cross. difficulties)

Orchidaceæ: that the in very many genera of this Family, the agency of insects is necessary for their fertilisation cannot be doubted, & therefore an occasional cross from another individual is probable.—Mr. R. Brown believes in this efficiency Cap insect agency, necessity, but adds that all the capsules of a dense spike being not infrequently ripening being ripened producing seeds, seems hardly reconcileable with impregnation by insects (Linnean Transacts. vol. 16, p. 704). I will therefore give a few facts to show how efficient insects are in the Family. It is known that in Orchis, Gymnadenia, Habenaria & Listera (other genus) the pollen-masses will not fall out cannot be shaken out of their pouches, & can be drawn out only by something touching the sticky gland; yet in a plant of Orchis maculata with 44 flowers open, twelve, beneath the buds had neither pollen-masses removed, but everyone of the 32 lower flowers had one or generally both removed: in Lis a stem of Listera ovata, every one of the 17 lowest flowers had pollen on the stigmatic surface: in Gymnadenia conopsea with 54 open flowers, 52 flowers had their pollen masses removed; in another plant with 45 open flowers, 41 had been visited by insects; in another individual I found three pollen masses on one stigma, in tho Four small plants of Orchis Morio grew in my orchard; I covered one with bell-glass;

(53

(Ch. 3. all plants cross, difficulties)

the other three plants had 23 quite or partially opened flowers & day after day a few days I found some of the pollen masses disappearing till all were gone with one the exception of one single flowered flower which withered with the pollen-masses in their pouch: but a few 2 or 3 one or two terminal flowers, which in each plant not included in the 23, & which opened subsequently never had their pollen masses removed. I then then looked occasionally at the plants under the bell-glass & found not one single pollen-mass removed; & though then left uncovered every flower withered in the course of six days without one with all single pollen-masses having been removed; from which in their pouches & the germens did not swell. From this fact, I infer that whatever nocturnal insect (for I never saw an insect visit the plants by day) haunts this flowers orchis had ceased th visiting them its visits it, as indeed might be inferred from the extreme terminal flowers of the three plants which had never been covered, retaining their pollen-masses.

I have repeatedly seen in flowers Listera ovata, Gymnadenia conopsea, Habenaria bifolia & Orchis morio, plenty of pollen on the stigmatic surface, but with pollen-masses of the same flower in their pouches; & still oftener the reverse case, namely the pollen-masses removed, but no pollen on the stigmas, — which clearly shows that each flower in these species are very frequently crossed by is very generally fertilised not by its own pollen, but by that of another flower or individual. After having

(54

(Ch. 3. all plants cross: difficulties)

attended to this subject at intervals during several years I have seen no insect visit an orchid, except once only twice a Butterfly suck sucking at an orchis pyramidalis & once a Gymnadenia conopsea; but Sprengel (Das Entdeckte &c. s. 409, 415) has been more fortunate for several times he saw a Hymenopterous insect visiting Listera ovata, which & he saw the pollen-masses removed & the pollen left on the stigma by these insects: on Epipactis latifolia, also, he saw a Fly with the pollen adhering to its back. I do not doubt that usually moths are the agents for for fertilisation; & I must think in the Butterfly orchis (Das Entdeckte s. 405) (Habenaria) the white-coloured flower, the nocturnal sweet smell at night, the abundant nectar contained in a nectary with which only a tube as fine as needle can be inserted all stand in direct & beautiful relation to the visits of nocturnal Lepidoptera.*—

[in pencil:] Entomologists have been often puzzled by finding their glands sticking to    & flower feeding Beetles.

It is well known that in certain exotic Orchidaceous plants, parts of the flower have the power of rapid movement, when irritated. In Catasetum Mormodes the pollen-masses are jerked out with such force as sometimes to hit a person's face; & I was told by Mr. Loddiges that he thought not one in a hundred would miss hitting the stigmatic surface: but I am not able to say what the result would be on the crossing of chances of two individuals crossing in this case, & with in that of those Australian genera (Lindley, Vegetable

[54v]

23 [+] 5 [=] 28

(55

(Ch. 3. All plants cross: difficulties)

Kingdom. 1853. p. 179), in which when labellum when touched by an insect suddenly turns round & shutting up the a box-like cavity, imprisons the insect. I am not able to ascertain-

(56

(Ch. 3. All plants cross: difficulties)

There ought to be woodcuts.

[sketch] Poor

[sketch] – stig

[sketch]

We now come to a case in which it appears, though the flower is open, that there is a direct mechanical provision for perpetual self-fertilisation: In in certain species of Ophrys, (in certain spe R. Brown (Linnean Transact. vol. 16, p. 739) has shown that the pollen-masses are retained by the gland & that they habitually fall readily fall out of their pouches, but being retained by their glands, & the stalk being of the proper length, they swing downwards, strike on & adhere to the stigmatic surface: hence insects as Mr. Brown remarks are not at all necessary for their fertilisation: to test this I covered up with under a large cone case of gauze several some plants of Ophry Ophry Ophrys apifera, so that no wing insect could not visit them or the wind agitate them, yet in every flower I found the pollen masses fallen on the stigmas. Again during three years I have examined many plants, sometime one day looking at every flower in 18 plants, of this Ophrys, & I have never saw same found the pollen-masses removed (except once by apparently a slug) or pollen on the stigma excepting of a flower excepting its own proper pollen. Hence I should have concluded that this was

(57

(Ch. 3. All plants cross: difficulties)

certainly a case of perpetual self-fertilisation; had it not been, firstly, that the sticky glands are here present, & if all insects did ever visit this flower* a cross might readily be effected, & secondly from the following consideration if they never do why are the glands sticky? Secondly in In Ophrys muscifera, the pollen-masses cannot be shaken out, as I have repeatedly tried; & therefore the agency of insects are is required as in the other Orchidaceous genera for their removal & apposition of the stigma; but upon examining 102 fully expanded flowers, during different years, I found if. those in in this number that only in 13 flowers had one or both the pollen masses been removed; in the other 89 withered flowers (most of them withered) the pollen-masses were still in their pouches. Hence those we see that the agent agency that in this species of Ophrys in Ophrys muscifera in the district in which I live*b the agency for the ordinary fertilisation of the plant is far less effective than in other orchids is deficient; & it may be that in Ophrys apifera the less important agency for an occasional cross is here likewise highly defective;—consequently that both species are here living under unfavourable conditions unfavourable in one respect, but so favourable in some other, that they are able to survive;—nor need we be surprised at this, as there are many cases of plants one kind living in a country, in which they seldom or never are known to seed.

But as seeding is the normal condition with all plants these very species in other countries or times; so may an occasional cross may possibly be the normal condition with Ophrys Ophrys apifera.

[57a (foll. 57)]

*a Mr. Brown suspects that the flowers of Ophrys resemble insects in order to deter other insects visiting them. But I cannot avoid feeling very sceptical on this head. As we shall immediately see in Ophrys muscifera the agency of insects seems requisite.

*In Spandow in Germany, Sprengel found that in Orchis militaris, of 138 flowers, only 31 had seed-capsules; & he attributes this to deficient fertilisation, & contrasts it with the case of Gymnadenia conopsea in which nearly all the germens had set.

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(Ch. 3. All plants cross: difficulties)

Leguminosæ. We now come to our last & perhaps most difficult case. The stamens & pistil are here beautifully enclosed within the keel as in a box shut up as in like a bivalve shell; & as the fl pollen is shed in profusion at an very early period, I am not surprised that Pallas & some other authors have advanced this great order as an instance in which a cross natural hybrid or cross, could never be naturally formed, yet if I trusted only to Sprengel's observations on the action of insects & to my own after having attended especially to these flowers during several years, I should have inferred that they could could not have escaped frequent crosses, between individuals of the same or another variety. The flowers in this Family are especially frequented by Bees, & I have seen on some them certain flies, butterflies & the minute winged Thrips, all covered by pollen. It is really beautiful to see what takes place, when a large bee alights on the wing-petals of we will say a common bean; how its weight depresses the wing-petals & with them the keel, by which the rectangularly bent pistil & ben anthers already shed pollen are forced out & rubbed against the hairy body of the Bee, as it visits flower after flower.

In many Leguminosæ the hairs beneath the stigma act in the prettiest manner to brush out the pollen in

(59

(Ch. 3. all plants cross: difficulties)

masses against the bee. Even such very minute flowers as those of the yellow clover no (Trifolium minus) are visited by Bees & the keel in them is generally split open: in Coronella after a hot day, when k I have seen the keel open of itself. But before anyone conclude comes to a conclusion on the part which insects play in the fertilisation of the Leguminosæ, long observation is required: for weeks together a Bee will not be seen even to look at a certain species, & then that species will suddenly be visited by thousands: Bees can suck the nectar as I have seen in the common Pea, without moving in the least the keels stamen & pistil pollen stamen & pistil pistil; but then again I have seen at another Bee time a Bee in whilst sucking cause stamen & pistil this flower cause force out the a pollen to protrude be forced out in profusion & get the its under surface profusely well dusted with against which the stigma was rubbed. against it other Bees will visit the already fertilised flower & collect the old pollen. Other Bees frequently bite holes at the bottom of the calyx & corolla & so get the nectar, without performing, what I believe is their proper function; aiding in any way its fertilisation of the flower whilst one Humble Bees are thus robbing the flower of the nectar corolla will hive-bees may be robbing it of collecting its pollen.

(60

(Ch. 3. All plants cross;- Difficulties)

But the case which convinces me that there is a direct relation between the structure of papilionaceous flowers & the agency of insects, is that of the Kidney Bean, (Phaseolus) which it is worth any one's while to notice: the tubular keel, with the included pistil & stamens, is here curled like a french-horn & has its little open end directed to the left right side: when a Humble-bee alights on the wing-petals, the tubular keel is so acted on that the pistil is protruded & the hairs on it brush out quantities of pollen, & the pollen & stigma are rubbed against the bee's side. Now I have noticed (which was overlooked by Sprengel) that the nectary is so placed as to induce both humble & hive bees invariably to alight on that side towards which the pistil & sti of pollen are is protruded. And that this is not a mere chance relation may be inferred from the structure of Lathyrus grandiflorus,* in which the keel, though not actually spiral is distorted towards one side, & again it is on this side ag that bees are induced invariably to alight, & in so alighting they cause the pollen to be protruded against them.

But now let us see what direct evidence we have of the crossing of our many cultivated leguminous varieties.

A. F. Wiegmann (Ueber die Bastarderzeugung 1828) asserts that by merely by planting together varieties of Phaseolus

[60v]

*a writer in Loudon's Gardeners' Magazine (vol. 8. 1832 p. 50) says that having observed that this plant never set its pods, be carried by moving the keel & so causing the stigma & anther to protrude, he found that the greater number of the flowers, thus treated, formed pods. But this does not always succeed (Ib p. 733), as may perhaps be accounted for by our climate being unfavourable to this plant. I should mention that Bees seem to visit this exotic plant only during certain seasons.

(61

(Ch. 3. All plants cross— difficulties)

vicia, Pisum & Ervum, he procured various hybrids, & that the seeds in the pure female parent were affected by the pollen of the other varieties; as these some of these crosses were bigeneric, I shd not have thought the statements not deserving of even allusion even alluded to these statements; had not the accurate Gærtner, a most hostile witness, (Bastarderzeugung s. 89) after the most very most careful & las experiments in artificially crossing the varieties of Peas, come unwillingly to the conclusion that the pollen of one variety does sometime affect the seed of the castrated female plant, in the same way as Gæ Wiegmann found happened with Wiegmann's plant, when

[For readability, Darwin's horizontal and vertical deletions are left uncrossed]

grown together. But I cannot myself yet arrived some degree of doubt from having observed that the colour of peas sometimes varies much, even when grown far from any other variety.

left spontaneously to cross with each other. The only possible error in Gærtners experiments, which I can see that is that it might have been the act of castration & not the pollen of the other varieties which affected the colour of the peas in the artificially fertilised pods. Undoubtedly Certainly in some varieties, as I have witnessed (but Gærtner selected the most constant) the colour of the pea varies much is extremely apt to vary.—I was led by their statements to apply to Mr. Masters of Canterbury, a great raiser of pea-seed & the author of an article on this subject, & he

(62

(Ch. 3. All plants cross— difficulties)

answered me that undoubtedly some varieties of Peas & Beans occasionally become crossed with other varieties, th but that he had never known a whole crop deteriorated. a But here again in these cases, I must remark that it must always be very difficult to distinguish in close varieties between the effects of a cross & of simple variation. Lastly it is incidentally asserted in the memoirs of the Board of Agriculture of New York (vol. 2. p. 100) that the varieties of the Kidney-bean easily cross with each other when grown together.

But now let us look to the evidence on the other side. A. Knight (Philosoph. Transact. 1799 p. 196) castrated several pea-flowers; on some he put pollen of other varieties, & some he left without any; & these latter did not set, showing that no pollen was brought to them by bees. Secondly I applied to Msrs — great raisers of seed-peas & they do not believe that their peas varieties cross, & they take no especial precautions to prevent it; & this seems to be the general practice of gardeners. Thirdly a friend had planted for me three during two generations, three varieties of Peas & three of Beans in rows of close together all in flower at the same time, & I saw their produce or third

[62v]

(a) Again in Mr. Sharp great seed nurseries* (Gardeners' Chronicle 1856 p. 823) it is said that Peas are grown very extensively & as they are considered liable to be adulterated, "considerable precautions are employed to secure separation."—

(63

(Ch. 3. All plants cross: difficulties)

generation & they seemed to run all true; but most of these varieties were closely allied, & between some of them a cross would not easily have been detected. Lastly, (& this case has struck me most) Mr. Cattell of Westerhaven regularly has beds of five varieties of the Sweet Pea, (Lathyrus odoratus) for seed grown close together; these varieties differ in no respect whatever except in colour, they they flower at the same time & are frequented by Bees; yet each variety comes up, as I know from experience, true.* Here certainly there can not be very little hardly any crossing; probably none whatever; but it would be rash to conclude positively that there was none, for I have noticed sometimes a plant of one variety growing amongst the others, which I have attributed to a stray pea having got into the wrong packet; but possibly these such might be the result of a cross*; for it is known that in very close varieties differing only in colour, the offspring sometimes are not intermediate but take after either parent: thus Kölreuter (Acta. Acad. Petropol. 1782 p 256) crossed red Hollyock with the pollen of yellow & the two seedlings were yellow; I crossed a dull purple Hollyock with the pollen of a bright yellow & the seedlings was pur red. he Kölreuter crossed a white one with pollen of red, & the several offspring were red, with one purple.—

[in margin, blue pencil:] [When I have] #

[63v]

I have failed in my endeavours to test this, for all the flowers which I castrated, both those on which I put pollen of other varieties & those which I left without any pollen fell off unimpregnated. This difficulty in manipulation is well known to hybridisers, & I presume explains the reason so few hybrids have been formed in this Family; I have heard of only two three viz one in the genera Erythrina & two in Cytisus.—

(64

(Ch. 3. All plants cross)

With respect, then, to the Leguminosæ, bearing in mind the facts given on their structure in relation to insects; bearing in mind Wiegmann & Mr. Masters & Msr Sharp statements; & on the other hand the opposed facts just given, more especially the case of the Sweet Peas, it is difficult to come to any absolute sure conclusion. But, I think, we may conclude that in a crosses between individual & individual, if such do ever occur, can take place but rarely in the Leguminosæ; & the facts here given with respect to the Leguminosæ seem to me more strongly opposed to the law, which I am attempting to establish, than any others, at present known to me.*—

(Space)

I will now sum up the discussion in this chapter, on the question whether it be a subordinate law in the mysterious act of reproduction that occasionally the concurrence of two distinct individuals is necessary. First for plants, the numerous cases of varieties which are known to cross freely if grown near each other;—the extraordinary precautions which hybridisers unanimously agree are necessary to prevent a castrated plant gathering receiving pollen from another individual, thus obliterating the action of the foreign pollen;—the many cases of dichogamous

[64]

With respect to the Leguminosæ it is difficult to balance the opposing evidence, which seems on the whole very hostile to the conclusion towards which occasional crosses taking place; & it may, I think, be certainly included if they do take place, they occur rarely.

[64vv]

* note to p. 64)

We have seen in a former part of this discussion, that forest-trees, when hermaphrodite, offer a difficulty to my notion of general crossing from the simple occurrence of very numerous flowers on the same individual close together. Therefore as the papilionaceous structure alone offers a difficulty, this is much aggravated in forest-trees belonging to the order, of which several papilionaceous division of the Leguminosae; of which, as I am informed by Mr. Bentham, there a good many in Tropical countries of gigantic size; & of which the Robinia, spendus acca pseudacacia offers a well-known example.

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(Ch. 3. All plants organisms cross— summary)

plants, or those in which the pollen is shed when the stigma are is mature at different times;—the many cases in which insects are necessary for the fertilisation of plants; & the other cases in which they are not necessary, but in which they are frequently visited by insects, & in which there seems an obvious relation in their structure to the visits of insects,—all tend to show that crosses between individual & individual must at least, be frequent. A camel-hair brush which may be aptly compared with the hairy body of an insect is found useful by hybridisers to bring pollen from flower to flower; but ask any one, if he were to brush away remove the pollen out of one flower with a brush, & use the same brush to bring foreign pollen, whether he could thus make a hybrid, & he will tell you that there would not be slightest chance of success.—

As it is known that protection from rain & damp is favourable to the fertilisation of flowers, it is singular remarkable how extremely general it is that the act takes place fully exposed. The reported cases of habitual fertilisation in within the bud or any closed chamber a really enclosed the closed corolla are comparatively very few; & as has been shown are mostly open to some doubt

I cannot but think suspect that such cases as that of

(66

(Ch. 3. All organisms cross)

Subularia, Podostemon, Goodenia (?) of Ophrys apifera, & even of swe the Sweet Pea & of other Leg papilionaceous flowers will be modified & explained with the progress of knowledge. Wh How comes it, with the almost infinite modifications of structure in the vegetable kingdom, that no case, as far as I can find out, is known of the sti anthers bursting actually on the stigma: in Goldfussia Stylidium there is a near approach to it, but here there is a wonderful contrivance of collect self movement & of collecting hairs, of nectariferous organs which I can hardly doubt would favour by the agency of use Be insects an occasional cross: in these many several of those cases in which the anthers move to the stigma or the stigma to the anthers, insects are requisite to excite the movement, & not only would favour a cross, but, in barberries Mahonias at least, crosses do frequently take place. What again is the meaning of the profusion superfluity of pollen in many hermaphrodite flowers?

[For readability, Darwin's horizontal and vertical deletions are left uncrossed]

in these dioecious plants, which are fertilised by the wind we at once recognise the meaning  if eternal self-fertilisation was not opposed to same law of nature; will it be said that the structure of the flower has been made such, that it requires mangled the quantityof Kölreuter has shown that in Hibiscus (Vorläufige Nachricht 1761. s 9. . & the statement is confirmed by Gærtner in his Beiträge zur Kenntniss. s. 346) sixty

[67a]

Gardeners' Chron. Nov. 21 1845. Article on there being 7000 pollen grains to every ovule on seed in Glycine – good as I mention because Papilionaceæ, as argument for cross impregnation. We see recognise use of numerous pollen grains in Zea; why not here?

14

x wrong reference

(67

(Ch. 3. All organisms cross— summary)

grains of pollen ([illeg]are sufficient to fertilise all the seeds in a flower, but the anthers of which he calculated had 4863 grains of pollen; but Hibiscus though hermaphrodite is a dichogamous plant, & therefore might require a very great excess: in Geum urbanum the pollen is only ten times in excess (Gaertner Beiträge &c s. 346): in the

60/4863/81/48/16

Gaertner thinks (Beiträge zur Kennt. s. 440) that this superfluity of pollen is simply for ensuring the fertilisation of the plant: but on this view it must be admitted that the generally flowers have been formed, without any object which we can see, with a structure rendering self-fertilisation so far difficult, that this difficulty is compensated by a great superfluity of so highly wrought an organic product as pollen!

On the other hand we can understand the act of fertilisation taking place so generally in open flowers,—the maturity of the pollen & stigma being at a different period times—the many & very curious relations of structure to the visits of insects—the superfluity of pollen—

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(Ch. 3. All organisms cross— summary)

the presence in closely allied groups of hermaphrodite & bisex unisexual plants,—if the occasional concourse of two individuals be a law of nature. From the well-known elective power between various kinds of pollen specifically different & the stigmatic surface, it seems to me not improbable that the pollen of another a distinct individual or slight variety may be prepotent over the flowers own pollen; & from the facts given of in regard to the greater vigour of the crossed offspring of varieties, I believe that such crosses would have a better chance of surviving in the severe struggle for existence to which all living beings are subjected, than the offspring of self-fertilisation.—

Although I believe good results from crossing & that probably the occasional concourse of two individuals is even a law of Nature, yet I come very far from supposing that such good is the sole cause good of the separation of the sexes, (which necessitates a cross each time); for all analogy leads to the belief that division of labour, to use Milne Edwards expression, tends to the perfection of every function.

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(Ch. 3. All organisms cross— summary)

Turning to animals, we have although many are hermaphrodite, we we have the remarkable fact that not one single land animal, in which a fortuitous cross is obviously impossible by the same agencies, viz insects & wind wh that are so efficient with plants, is hermaphrodite in the strict sense of the word or self sufficient. Again amongst aquatic animals, not one case is positively known, in which the structure renders a a perfectly enclosed structure render would render a fortuitous cross impossible; & that in aquatic animals fortuitous crosses are not improbable we may infer from the fact seeing that many fixed marine aquatic animals have separate sexes. These facts, & others identical with those just referred to under plants, as to maturity of the ova & spermatozoa at different times, we can understand if the occasional concourse of two individuals be a necessity; & I think it would be difficult to offer any other explanation.—

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(Ch. 3. All organisms cross: summary)

If it be asked why the occasional concourse of two individuals should be a law, I think the facts given showing that the crossed offspring of two varieties, & even of two individuals in hermaphrodite plants, acquire increased have their vigour & fertility increased, may afford a sufficient answer. Even the hybrids from between distinct species gain in stature & vigour compared with their pure parents; & in some strange cases even their deteriorated fertility which is always deteriorated seems somewhat improved by further crossing. (a)

on the other hand close interbreeding, aversion

It would appear as if the good from crossing was like that felt by the individual from some slight change in the conditions of its existence. But if it be further asked, why changed conditions should act well on do good to the individual, & why a slight cross should injure add to the vigour & fertility of the offspring, no answer can be given, or can be expected seeing how utterly ignorant we are in regard to Life & its Reproduction.—

Finally weighing all the evidence as well as I can, I certainly think that it will hereafter

[70v]

(a) text

On the other hand close interbreeding, even in animals with separated sexes in which a cross, necessarily a between two individuals, is a necessary accompaniment, seems injurious.

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be proved, that the occasional concourse of two individuals, & these individuals not very closely related, of if closely related is a subordinate Law in Reproduction.—I have stated in full all the difficulties opposed facts in full facts opposed to this view, which are known to me, but have not given a few of those all those strongest fact in favour of this view it. The difficulties which many of which are as we have seen are grave enough, I must leave to the judgment of the reader.

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on the changes of condition causing lessened fertility or complete sterility.— (all used to p. 102)

As we have in this chapter so largely discussed the good apparently derived from crossing varieties & individuals, & from slight changes in the conditions of existence, it will be convenient here, also, to discuss the effects of those changes which lessen or quite destroy the fertility of organic beings; (a) though the subject is, I think it will be seen, more intimately related to hybridism than to the points hitherto treated of—

bears on[Hyaena], & likewise indirectly but in an important manner on the fancy case of variability.

There is a wide difference, as strongly insisted on by Isidore Geoffroy St. Hilaire (   ) between taming an animal, & getting it to breed in captivity, which alone can be called domesticating it. The one is very easy, but domestication, as the experience of all ages shows, is very difficult. One's first impulse is to attribute the whole difficulty to the sexual instinct being affected, as has often been the explanation with respect to the Elephant in India; & in the case of birds in some instances to a proper place or materials for nidification. This in some instances may be a sufficient explanation,

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but in very many cases, animals couple but but do not conceive, or but very rarely or even never conceive; & here it cannot be an instinct which fails: moreover we shall find in plants a large & parallel series of facts.—

Why many animals taken young, perfectly tamed, quite healthy & living long, should not breed, it is impossible to explain. One must attribute it to some change in the conditions of its existence. Sometimes one may infer that it is not owing to any change of climate, as when captive animals will not breed in their own native country; in other cases it would appear not to be caused by want of exercise; in others not by change of food. Perhaps it may be due to these several slight changes combined.

Some orders are far more affected than others, without any assignable reason; but it often happens that certain species in such the orders usually least affected will not breed; & on the other hand that some species in those orders most which are generally most affected some will breed.

In some cases the animals are never known to couple; in others they do couple but never or most rarely produce young. An apparently very slight change in the condition of existence has sometimes caused an animal to breed, which had not never done so before.

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small type

(I will now give some facts. [pencil insertion:] selecting those which have illustrations

My materials are derived from scattered notices; from an M.S. report from the Zoological Garden, between the years 1838 & 1846 inclusive, of all the animals which were seen to couple & of those which produced young; from subsequently published Reports, & from inquiries which I made from the keeper of the Birds at the Surrey Zoological Gardens, I should premise that I have no doubt that no under very slightly different management, as in other menageries, the results would be somewhat different; & that in the long course of years individuals of the least fruitful species would be found to produce young under the same treatment which rendered all other individuals sterile.

[pencil insertion:] It is other than [several words illeg]

(First for the most notorious case of the Elephant, in its native country of India, has though kept in great numbers in perfect health, has with one or two exceptions, been never known to couple; but if we go

[74v]

I lay particular stress on animals not breeding when thoroughly tamed & left considerable liberty in their own country—

In menageries very many do not breed, or breed rarely & produce few young.—There it must be at first though not ranging & attributable to ill-health, but some live long & [3 words illeg]  away like sheep as highly fertile—We shall now see that the lessened fertility runs in classes without any apparent rule—Instincts.

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In captivity. The Four or five wild animals wild species of the Horse family genus, which have been brought into this country have all bred in Europe, but generally has often or after either one species with another producing hybrid here; though the conditions of their existence must be very different from those of their native life desert home.— Most wild species of the Pigs again breed readily; & the Peccary has bred in the Zoological Gardens; but this animal, in its [text excised]

[75v]

Procyon

Nasua Cuati

Potos — (Cercoleplis)

Taxa Blain

Gulo

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(The carnivora generally breed nearly, or quite as freely, as the Ruminants in captivity, but the plantigrade division must be excepted. Bears of several species couple most freely in the Zoological Gardens but with the exception of the cinnamon bear, have never bred have bred only twice thrice. I have heard of two occasions the Badgers breeding having bred twice, once in Germany (Wiegmann's Archiv. fur Naturgesch. 1837. p. 162) & once in the Zoological Gardens; I suppose it must be very rare in Germany, as the fact was published. The Cuati or Nasua in its native country of Paraguay, though kept in pairs for many years, & perfectly tamed has never been known to breed there, or to show any sexual passion. (Rengger. ib. p. 106)

So according to this same author it has been thus with two other plantigrades Procyon or Raccoon, & the Gulo: these three genera, have been kept in the Zoological gardens, & the two former have been known to couple, but none have never bred.— With In the Dog-division Family of the Carnivora, it is very different, as most breed, but it has very rarely taken place with Foxes & Jackalls.—In the Cat Family, breeding is espec likewise very general; but even here they couple far more freely than conceive; in the M.S. return from the Zoological Gardens for eight years the former coupling was noticed between various species 73 times, but young were produced only 15 times. It is remarkable that on a change of treatment with the carnivora at these Gardens, & when they were freely exposed in open cages to a much colder temperature, they were found to breed very much

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more freely. I have never been able to hear of the Tiger, though known to couple, breeding in India: nor does the hunting Leopard or Chetah; but this latter case the fact pains may have been taken to prevent their breeding, as the only animals which have hunted in a state of nature are alone worth taming. (Sleemans Rambles in India Vol. 2. p. 10)

Every one knows under what unnatural conditions, shut up in a small cage, the Ferret breeds; & even the otter has once bred in the Zoological Gardens; whereas the Herpestes griseus, though many have been kept in the gardens, & some species of Viverra & further Paradoxurus have never bred there.

In regard to Rodents, the Rabbit breeds most freely in wretched little hutches, as does the Guinea Pig, where the common Hare, though it has many times been tamed, most rarely will breed. Some few other Rodents as the Chinchilla have bred as the Chinchilla, some mice, a porcupine, a Lemming have bred in the Gardens; some have coupled & never bred & some have done neither. To give one example no Squirrel Sciurus, has ever bred, though the Sciurus cinereus has been known to couple, & as many as fourteen of the S. palmarum have been kept together. Nor have I ever heard of the English squirrel breeding in captivity. How can we

What a strange contrast to the free breeding of the rabbit, guinea-pig & white mice!

Lastly in regard to the many species of Monkeys; most of most couple freely, but during the eight years, of which I had a return, there

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Both the African, American & Australian Ostriches have often bred in confinement: yet what a contrast change in habits, climate & nature of food they must have suffered!—Most Gallinaceous birds breed very fre brought from all quarters of the world, breed very freely.

(We see what an astonishing change the Guinea-fowl, from the dry deserts of Africa; & the Peacock from the jungle of India have undergone, & yet breed freely.) At Lord Derby's some Ortyges, Grouse, & Poeven Partridges have bred. The Capercailzie has bred in the Regents Park; but in Sweden it has been found (   ) that the grouse would not breed without the birds were kept in a space, though small one, of enclosed wood. a space of wood was enclosed so as form a la

On the other hand it is well known that Partridges will not breed in captivity; but one case is recorded of the red-legged partridge having bred is on record (Journal de Physique Tom. 25. p. 294), when kept in a large court with other birds.

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Birds. We have seen that the Carnivora, with the exception of the plantigrades, breed pretty freely in captivity; but the case is very different with Hawks. It is said that

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(Ch. 3 Sterility) Animals)

Pigeons, again, breed readil much more readily than most birds in confinement: in the return from the Regents Park for the eight years, thirteen species bred, & only two were seen to couple with no result.—Both the magnificent species of the crowned Pigeons have bred in the Gardens; but Mr. Crawfurd informs me that nearly fifty birds were kept in a pleasure ground for several years in Prince Edward Island, near to their in a climate one would have thought admirably adapted to them, & that they never bred.

(Parrots, of which such numbers are kept & which have often lived to such extraordinary ages, showing that they are healthy, breed so rarely that paragraphs in the newspapers (Athenaeum 1843. p. 829. Brit. Assoc. Report) are sometimes inserted when such occurs: in the Regents Park, & in the Surrey Zoological Gardens some few species couple, but I believe the Australian Euphema pulchella is the only species which has ever produced fertile eggs: Sir R. Schomburgk says (   ) that Parrots kept tame & loose in Guyana do not breed.—What a singular & inexplicable contrast is thus presented by Parrots with Pigeons.—

Of the small birds or insessores, several as the linnet, Goldfinch, Siskin &c are known freely to breed, or rath with the canary bred in confinement; but very many others, as the Bull-finch have never with the exception of one or two crosses with the Canary, have never been known

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to breed. Though Larks, (Alauda) of four species are kept in numbers, & I have known of some which lived in a large aviary for seven years; yet not one none, as I have been assured by a great Bird Fancier, here in their native country have ever been known to breed. In the 8 year return from the Zoological Gardens, I have particulars of 24 confined species which have never bred, & of which only four have been known to couple.

Waders or Grallatores, as a class, seem eminently sterile in captivity; but many of them are short-lived in this state, so that the fact is not so remarkable as it would otherwise be.—I have heard only of three breeding: namely a Water-Hen (Gallinula chloropus) in the Regents Park; a Crane (Scops paradisea) at Lord Derby*, & another Grus antigone at Calcutta. (*The Knowsley Menageries 1846. PI. xiv.—Mr. Blyth Report of Calcutta Asiatic Soc. of Bengal, May. 1855).

The great Duck Family, Anatidæ, seems the most fertile of all, perhaps apparently more so than even the Gallinaceous birds or Pigeons; yet one would have thought that their conditions of existence, considering their aquatic & generally wandering habits & insect food, would have been singularly affected by confinement. Between 20 & 30 species have bred in the Zoological Gardens. On the other hand, Sir R. Schomburgk says (Geograph. Journal vol. XIII. 1844. p. 32) says

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that he has never heard of the Dendrocygna viduata, though easily tamed & frequently kept by the Indians of Guyana, breeding.

Lastly with respect to Gulls (Larus) & Pelicans, though kept in numbers in their native country, in the Regents Park & Surrey gardens, are never known to couple or to breed, with the exception of the Herring Gull in the 1850–51, in the Regents Park. But their condition of existence & food, it might have been thought, would have been not more unnatural than with marine Ducks in confinement.

in lower animals we find such analogous fam

Insects seem to suffer in their fertility like the larger animals.

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I have been informed in the Regent Park Zoological Gardens that even those mammals & Birds, which do breed in confinement very rarely breed for the first year or two. The secondary male characters seem sometimes to be affected, as in the case of the crimson breast of the Cock Linnet bei loss of the brilliant colours of many cock birds under confinement. (Bronn Gesichte der Natur B.2. s. 96: Phil. Transact. 1722. p. 278.) Beckste large Birds & the brilliant plumage of several other birds, almost is best in confinement

The young when born are apt to be born dead die or to die immediately,—of which fact Rengger gives several instances in Paraguay: the flow of milk is often checked;, which all shows disturbance in the reproductive functions. I have fancied that even the strangely perverted maternal instinct, so frequently leading animals in confinement to devour their youn new-born young, may likewise be connected with the same general disturbance.

Small Type

Considering all the facts which I have been able to collect, & those most of which I have thought worth giving given, it seems impossible to come any more definite conclusion, than that captivity has an especially injurious influence on the reproductive system; & more injurious in some orders than in others, but with many exceptions in every case. Generally, the cause can hardly be generally change of food, for the difference in the effect produced by captivity is vast, when we compare

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carnivorous mammals & birds; nor can it be generally want of exercise, when we consider for instance the case of Ostrich tribe, so cooped up in confinement, & ranging so widely in their natural state: nor can it be generally change of climate, when we see so captive animals so frequently sterile in their own climate.

(The case of domestic animals, perhaps, is hardly appropriate with respect to climate, as it may be said that their constitutions are ensued to change; but it is remarkable that those Dogs, as the Bull-Dog, which degenerate in India, yet breed freely there as I am informed by Dr Falconer, as do likewise, according to Dr Daniel Bi dogs imported from Britain into Sierra Leone. From the latter country, I have received owing to the kindness of Dr. Daniell, Poultry & Pigeons, & though brought here in Autumn & so exposed to a great change of climate the males were ready at once to procreate their kind. Rabbits breed pretty well in India. The only instance of which I have heard of the fertility of domestic animals having been affected of which I have heard, is that race of Geese & Poultry given by Roulin when first imported into Bolivia (Bronn Gesichte B.2. p. 100) the West Indies, which according to [Gavilassium] were at first reared with much difficulty: Dr. Falconer, also, informs me that the eggs of Turkeys in the hot & dry province of Delhi are extremely apt to be infertile: Geese, of [illeg]

 

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as I am informed by Mr. Crawfurd, will do not lay at Manilla.

Lastly we cannot generally account for the infertility of animals in captivity by the want of health, for many of them live to old age; & in the case Hawks, used for Hawking, must have been in robust health. Moreover the diseases of which animals die in menageries, (& numerous post-mortem examinations of the cases in the Zoological gardens have been published in the Veterinary Journal), are chiefly inflammations of the internal viscera & membranes, & tubercular disease cases. Such diseases are known in mankind not to affect the reproductive system. Of all domestic animals, the sheep, perhaps, is the most subject to disease, yet it is very fertile. In captive animals, the reproductive organs, do not appear to be diseased; but their proper function is gravely often most gravely interfered with. The case seems quite an especial one: I do not know if there is any are instances of any other organs, not diseased, yet not performing their function. We can attribute this deficient action only generally to general constitutional derangement.

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(Ch. 3 Sterility.— Plants)

Plants.— We sh In the vegetable kingdom there is a large class of facts in regard to sterility analogous with those in the animal kingdom. But the subject is here much more obscured by several considerations, which will partly be noticed.

It is notorious that very many plants in hot-houses & in our gardens, though living in apparently the most perfect health, & often more vigorous than in their native habitat, never produce seed. I do not allude to the cases in which the seed-pod, for want of heat or other causes does not ripen, (though this may be analogous to the frequent births of dead anim offspring in menageries) but to such those cases in which the seeds ovules, as far as we can judge, do not set. are not fertilised. Many productions of the temperate region, for instance most of our fruit trees, when grown in hot cou tropical countries do not flower; so it sometimes is with plants in our own country when treated with an excess of manure or kept too hot & damp in greenhouses: but it seems very very doubtful whether such cases come under our present subject, for here the reproductive individual is here not c produced, & therefore cannot be considered classed as sterile. (a) But there are many foreign plants in our gardens, which do not seem injured by our climate, in which the pollen seems perfectly good, & in which the pistil seems perfectly formed, which nevertheless never or most rarely set their seeds. [faint pencil note:] Insert — Description — But a rat under [illeg] or wd be [3 words illeg] These cases seem analogous to those

[86v]

To check over luxuriance, gardeners in India mutilate in the oddest way European plants which they cultivate.

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(Ch. 3 Sterility.— Plants)

of captive animals, in which the reproductive system seems far more sensitive to change than any par other part of the organisation. [faint pencil note:] I will, [many words illeg]

Linnæus long ago remarked (Swedish Act. vol. I 1739 p. 3.— Pallas makes the same remark in his travels vol. i. p. 292) that alpine plants when cultivated in gardens, though naturally in their natural site loaded with seed, produce very few or entirely abort; but with great care, some & planted in favourable situations some will produce abundant seed, as in the case of Draba sylvestris, "one of our most thoroughily alpine plants" (Cybele Britannica vol 1. p. 131) which sows multiplies itself by seed in Mr. H. C. Watson's garden. Zuccarini has remarked (   ) that scarcely any of the section genus Oxalis from the Cape of Good Hope will not seed in Europe. (a) Many hardy liliaceous plants are quite sterile in our gardens; as are many exotic in our houses green house; as are many Bog plants: Herbert has remarked numberless instances could be given: but in some of these cases the subject is much obscured by what Gærtner has called contabescence, namely the abortion of the anthers, which in some cases at least seems to be in no way connected with any change of conditions; but I shall have to return to this subject.

(There are several cases on record, as in Lobelia, Passiflora, Gladiolus, Lilium candidum &c, of plants having good pollen, as known by its fertilising

[87v]

Syringa Chinensis

Perica

vulgaris

[87vr]

To give one example of a plant, apparently perfectly hardy

[87v]

(a) In the genus Syringa, which seems perfectly hardy in our climate, I cannot hear that the Persian or Chinese Lilac ever set their seed; & I find that their pollen in water does not swell like that of common Lilac, which does produce (I do not know whether always) seed, which have I have found to germinate: whereas in Germany, Gærtner instances (Beiträge zur Kenntniss. s. 560, 564) the bush common Lilac, as have never producing seed, though having well-formed seed capsules, in the same manner as many quite sterile hybrids here.

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other plants, but in which the female organ either cannot be fertilised anyway, or only by pollen of another individual or other species xx (see Gærtner Bastarderzeugung s. 333, 356, 66): some of these cases may be special cases, like those cont of the contabescent anthers, but as they generally occur in exotic genera, they are probably due to something unfavourable in the conditions of existence the cultivated plants.)

Pollen, when once in process of formation does not appear easily injured; a plant may be transplanted or a thus branch may gathered with flowers in early bud, & if placed in water the pollen will be perfectly matured. But the female organs seem much more sensitive, for Gærtner found (Beiträge zur Kenntniss. s. 252, 333) that generally with dicotyledons, that mere previous transplanting, even if the plant did not flag at all & serve if v, prevented the act of fertilisation; & this resulted even with plants in pots, if the root had grown out of the hole at the bottom but this did not occur in all but in some few cases as in Digitalis the transplanting did not prevent fertilisation. & According to the testimony of Mauz, Brassica rapa ripened its seed, with the plant pulled up & placed with its roots in water, as do have done several monocotyledons when cut from their roots. But I do not know whether in these plants had been cases the flower had previously been fertilised, for this, judging from W. Herbert experiment on Crocus makes a great difference; for he found that after the act of fertilisation, neither transplantation or mutilation flower after fertilisation set perfected their seed; but that after prevented the seed from being perfected, but that after transplantation "no application of pollen of its own pollen would fertilise the flowers after the transplantation."

(Journal of the Horticultural Soc. Vol. 2. 1847. p. 83)

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In accordance to the nature of the species acted on, excess of food or manure, & some believe especially ammoniacal manures, will produce sterility. Nothing is easier, as I have tried to produce on some plants, as the common cowslip primrose, absolute sterility by manuring it too much.

Plenty of perfect flowers are produced, but these produce no seed, or seed which will not grow: Gærtner also (Bastarderzeugung s. 370) gives alludes to the copious excessive flowering of some sterile species, & compares the fact to the excessive flowering of sterile hybrids: in other cases too much manure, especially if accompanied by too much heat, as before alluded to, prevent flowering. The effect of much manure depends on the nature of the plant; in some cases it is hardly possible to give too much; & Gærtner enumerates (Beiträge zur Kenntniss s. 333) Gramineæ, Cruciferæ & Leguminosæ as standing much manure, whereas succulent, & bulbous-rooted plants &c will s are thus easily rendered sterile. Hence in some case potting by checking the supply of food increases the fertility of hybrid plants, & in other cases lessens them. (Gærtner Bastard, s. 378 s. 519: Kölreuter Act. Acad. St. Petersburgh 1781 Part II p. 303.). The extreme poverty of soil seems to have much less effect than too much richness on causing sterility, although of course the number of seeds is lessened, owing to the lesser size of the plants: but in

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some plants of Trifolium minus & repens, growing flowering on an old lawn never manured, not one seed seemed to be produced: some other plants produced very few. I have tried starving kitchen garden plants & very small & few Pods can be produced. Herbert in Hort. Journal on Crocus Crocus

The period of growth at during which wa the plant is watered often affect seems to affect greatly the fertility of a plant; so also does bottom heat. Many Man Many pelargoniums are extremely sterile (many of them no doubt owing to their being hybrids) but seeds have been obtained from some by extremely slight changes in treatment. So Kölreuter (Nova Acta Petrop 1793. p 391) after comparing the manner in which some pure species of Mirabilis shed their flowers like hybrids, says that some were rendered more fertile by being kept dryer in pots. Very slight changes in position as on a slight bank, instead of at its foot, will sometimes make the difference, of a plant setting seed which appeared equally healthy in both positions, setting its seed or not producing one.—

No doubt temperature has a very important influence on the fertility of plants: but it is surprising what changes changes, in this respect some species wh will bear to which they are not naturally subjected. To give one example; Dean Herbert showed me in his garden Zephyranthes Candida seeding well after having been just covered by

Lilac

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snow; but this plant, he informs me is a native of La Plata, where snow does not fall; & it runs wild & spreads itself in the dry & hot climate of Lima.—

Many  [in margin] maizeSeveral cultivated plants, like domesticated animals, will endure the greatest change of climate & yet retain their fertility; & what makes the case far more remarkable, have their natures so far changed that their pro chemical composition is sensibly modified: thus Dr. Falconer informs me that both Hemp & Flax seeds well on the plains & on the mountains of India, but its fibre is brittle; Linum does the same, but its seeds contain 25 per cent more oil: the poppy contains on the plains much large proportion of more narcotin in proportion to morphine; & in wheat there is a similar difference in the proportions of starch & gluten; yet these plants in both situations seed well.—I suspect cultivation allows a plant to undergo change without sterility.

Contabescence

I have alluded to the more or less complete abortion of the anthers, called by Gærtner, contabescence: until I read Gærtners able discussion on this subject, (Ken Beiträge zur Kenntniss &c s 117 et seq.), I attributed all these causes to sterility from changed conditions. The cases are very numerous: Kölreuter gives many (Zweite Fortsetzung p. 10, p. 121—Dritte F. p 57.) in Dianthus & Verbascum: Herbert (amaryllidaceæ p 355) adduces to case of the N. America Azaleas,

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which anyone may compare (as I have often done) with the most sterile hybrids, & the anthers will be seen found to be in exactly the same aborted condition. Gærtner has shown, that the contabescence varies in different plants in intensity;— that it occasionally affects very many plants species in all classes but is most apt to occur in certain orders, as in Caryophyllaceæ, Liliaceæ (& Ericaceæ may, I think be added);—that when one flower is affected generally all ge are affected;—that whatever the degree of contabescence may be plants propagated by cuttings, layers etc retain (s. 149) the same degree of contabescence;— & that it comes on at a very early period in the bud. (These facts alone, would not have convinced me that contabescence was due to some cause distinct to exposure to unnatural conditions; for in plants, very differently from in animals, we may I think infer that the fertility of the reproductive individual or flower is far less fully as much affected by exposure to which it is subjected conditions to which the whole plant, or vegetative individuals are have been exposed, as by those to which the reproductive individual itself is exposed; we see this in the effect of previous treatment on the bearing of fruit trees, & this perhaps would account for contabescence coming on very early in life, & for all the flowers on the same plant being affected. But Gærtner further

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shows that contabescence, when it once comes on, is permanent (with one exception) far in degree for life;—that it can I can be propagated by layers cuttings &c;—that no change in treatment, as potting &c affect the degree;—that possibly it is doubtfully hereditary in hybrids from a contabescent plant;—& lastly that the female organs generally not affected or only rendered precocious, & that in some instances in which after artificial fertilisation the seeds were counted, the full normal number were produced. & lastly that many indigenous plants are affected by contabescence. These two last facts facts more especially the last one seem to prove that in them the quite incompatible with the view that contabescence can be caused by unnatural conditions of existence; for it seems incredible that the female organs should not be at all affected whilst the male were rendered completely sterile: some degree of inequality of affection would be not at all improbable, from the very frequent production of hybrids in those captive animals which very rarely produce pure young in confinement. Moreover many endemic plants are contabescent, which seems equally incompatible with the above view. On the other hand One potent cause of contabescence probably is a tendency to dioi become dioicous, as indicated by Gærtner in the case of Silene; & that may have nothing to do with external conditions. On the other hand, as exotic plants seem very often affected; & as Kölreuter (Dritte Fortsetzung s. 57) seems to think that it is most apt to affect indigenous plants, when transplanted into a garden; & as Wiegmann

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(Über die Bastarderzeugung s. 27) states that the contabescent plants wild plants of Dianthus & Verbascum which he found, grew on a dry, sunny sterile bank, the affection may in some instances be due to exposure to unnatural conditions. Anthemis nobilis.

Double flowers: seedless fruit.—Flowers are often rendered made, (as commonly expressed) double nearly or even quite infertile by doubling. The male organs are much more often & earlier affected than the female, as everyone may see. (Gærtner Bastardzeugung s. 363 s 569). pod seed) not healthy) The tendency to double depends on the nature of the species; for we have some species extremely double, as the Gorze, in classes which very rarely have double flowers. It depends, also, on the structure, as flowers with many stamens & petals are most apt to become double. Luxuriant growth & Rich soil no doubt are highly favourable to doubling; & Prof Lehmann (Quoted by Gaertner Bastard. s. 567) found several wild plants double near a hot spring: on the other hand I may mentioned that I found many stunted wild plants of Gentiana campestris, (Gardeners' Chronicle.   ) growing on a very poor chalky bank very double; I have also noticed a Staphylea & Aesculus pavia, & some other plants growing very poorly under favourable conditions, with a distinct tendency to become double: therefore luxuriant growth & good soil are not absolutely necessary concomitants.

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Again when the fruit is largely developed seeds are rarely perfected (See Prof. Lindleys excellent remarks on this subject in Theory of Horticulture p 175–179) we see this in our best pears: the Enville pineapple which is a poor one is the only kind having seeds: this is notoriously the case with the Banana & Bread-fruit; it being extremely rare to find even a single good seed, & these only except in some very poor varieties. (So again it is generally believed that a great development of tubers or roots often (certainly not always as in carrots, turnips &c) causes infertility; as does a great tendency to propagate by runners, & suckers.

In These several cases affections have always been considered as the causes of the lessened or destroyed fertility, owing to an sort of antagonism or compensation in growth. I strongly suspect the effect has been here held for the cause.

I do not doubt that if any cause whatever produced a great development, especially if in the proximity to the reproductive organs, this would tend to produce infertility: but we have to consider why is cult what so frequently gives in cultivated plants the development with first tendency to this such development often in connection with lessened fertility. There can be no doubt that having the first tendency having been given, the selection the selection, taking advantage of the hereditary principle has played a most important part in nearly every case, & as we know

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in the history of several double flowers, in which the work commenced in sayingthe seed of a flower having one or two stamens converted into petals. I believe that the first cause is lessened fertility from the plant being exposed to unnatural conditions, more especially to excess of food; & that the doubling of the flowers, the great size & succulence of the fruit, of the roots, & the tendency to form suckers &c is the compensation result of, or is compensation of organic matter not being required consumed in the formation of seeds, together with generally an excess of food the process having been perfected by man's selection. I have come to this conclusion, from finding an exactly parallel series of fa cases facts, but not perfected & added to by continual selection in a case in which lessened fertility or entire sterility has supervened from an entirely independent cause; namely from hybridity. Gærtner has shown that (Bastard. s. 565) that hybrid plants are more inclined to produce double flowers than pure species; & the tendency is hereditary; in hybrids & in double flowers the male organs are first affected; in both there is a strong tendency to pro yield innumerable flowers. Again Gærtner insists (Bastard. s. 537)

"Fruchtungsvermögen des Bastard: diese Eigenschaft ist sehr ausgebreitet bei den Bastarden." s. 537)

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most strongly on the very general tendency of hybrids, even utterly sterile kinds, to produce fruit the caps perfect receptacles of the seed or fruit: thus, Sabine on Passion Flower.

With respect to the development of roots, Kölreuter expresses his unbounded astonishment at the size of those of hybrid Mirabilis. All hybridisers, also, (Gärtner Bastard. s. 527) are unanimous in the strong tendency in hybrids to be propagated make larger increase by their roots, & throw up suckers &c.—

Considering this strictly parallel series of facts, & that it can hardly be disputed that unnatural conditions have a special action in lessening the fertility of organic beings, it seems to me, that the view here adopted, that the lessened fertility is the first cause aided by excess of food & selection, & that that double flowers, fine fruit, large roots, &c is the result. Therefore the enormous class of facts here alluded to, come, I think, fairly under the present discussion,*a & support the conclusion that considerable changes of condition have an especial action on the reproductive system. I may add that horticulturists have often

[96v]

p. 96

* How far the several curious known & extraordinary cases of plants never flowering or never seeding in their native country, when they are abundant, come under our present subject, I am doubtful. Certain plants ascend mountains to a height, & in the arctic regions to a latitude in which they do not produce seed. In such cases I should suppose that I presume that there can be no doubt that their infertility is owing to the climate to which they are exposed, but that they have some other advantage over their few competitors in these sterile regions, which allows them to hold their own. So again  We may suppose this to be the case in the curious fact instance mentioned by Kalm that the coniferous trees which make cover in an impenetrable mass the swamps on the shores of N. America, never seed there; but only on the when growing in the higher country. Certain water-plants in our own country rarely or never seed. Dr Bromfield (Phytologist    ) gives a still more curious

instance, namely in the common ivy which abounds in Russia & over the North of Europe but never flowers.

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spoken of infertility as the bane of horticulture; but on the views here advocated they ought to confess that they likewise though this may be so, they owe to it, their choicest productions.— (Lead)

Although we have seen so many animals in captivity & so many plants under cultivation are rendered more or less sterile infertile: yet in those animals which do submit to domestication, there is certainty or the the particular changes of conditions implied by domestication, there is nothing which there is are far from bearing any having their whole the fertility checked; on the contrary the more abundant & regular supplies of food which most domestic animals probably receive in comparison with wild ones, appears, as might have been expected, to increase their fertility. Bechstein (B) I have compared the produce of nearly all our (a) domestic animals, with their wild prototypes, when known or with the most nearly allied animals. Of course there is often doubt about the rate of increase of wild animals, but as far as known all domestic animals, without it be the Peacock, bear their young at a great either a greater number of young at a birth or at shorter intervals, probably at a younger age, than wild. In some instances domestic animals selection

(U)

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B If it be denied that domestic animals which are often fattened & which are protected from famine, do receive more food on average than wild ones then I know not how to test the dictum

Bechstein—Ferret, Rabbit—Wild Pigeon Poultry

Bechstein

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may have increased their fertility, by the most fertile individuals, but in others as in cat, Pigeons &c I do not suppose this point has ever been attended to. In regularly cultivated plants, some as we have seen are nearly sterile; but these are such as can be propagated by cuttings, grafting &c; & in most of these the incipie infertility, in accordance with the views just advocated has been of use, as causing greater development of some useful product, & therefore here infertility has been selected. (U)

In many plants, cultivated for their seed, selection may probably will have increased their fertility: but there are many other plants propagated by seed, but yet which would never have been selected for this advantage; as the carrot, parsnip, cabbage, asparagus. As in these instances the wild prototype is known, I have taken the finest wild plants which I could find, & ordinarily fine cultivated plants, & I find that the cabbage has about

[faint lines in pencil:] In carrot I did not measure but after selecting the finest wild plant compared it with—The wild one grew in cultivated ground & had more than those growing in natural ground.

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I have alluded to this last subject more particularly on account of Mr Doubleday's* theory, which is that an abundance of food checks fertility & poverty increases it or "that prolificness is in the ratio of the state of depletion". Independently of mankind, in regard to whom, I should have thought that the Malthusian explanations moral certainty of early reckless marriage in the one case reckless restrained or & deferredreckless marriages, would have accounted for the asserted facts, the only evidence appears to me the undoubted fact that you can fatten individual animals to such an excess, as to check their fertility;*a & that in plants you the same can be easily done by excess of manure.(a) If indeed it could be proved that the most flourishing wild animals & plants, which existed in the greatest numbers in any country*(a), were from this very cause of their flourishing so much, had their fertility checked, it would be a most serious difficulty objection to the principles hereafter to be elucidated in the chapter on selection. But to me, all the facts seem to point in an opposite direction.— conclusion (Space Lead)

(U)

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*Gærtner in his Bastardzeugung s. 378, gives references to Henschel & Girou de Buzareingues, that in domestic animals produce more in fruitf fruitful years, than when food fails.

But in plants we have seen that there can be no question that by poverty of soil the number of seeds can be lessened. No one can doubt that few ears of any corn will be produced on very poor land than on rich.

In the cases of the most wonderful increase on record, namely that of the domestic animals become feral & rapidly spreading over America, can it be believed, that this astonishing increase was owing to lessened fertility, for want of food: if there was any change whatever in fertility, which may be doubted, in all probability this would be increased.

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In concluding this chapter, it must be admitted that the evidence on the several points discussed in it, has been often very dubious & partly rests on the weakest possible grounds general belief. Yet to my mind the evidence does seem to weigh in favour of the following conclusions; that slight changes in the condition of existence are favourable to the life of both animals & plants;— that in both, close interbreeding between the nearest relations is unfavourable to vigour & fertility, & that, on the other converse hand, crossing with either a distinct individual or variety (& even distinct species in some respects) is favourable in all respects; & su further that there is some probability, though many of the gravest difficulties are at present stand in the way, that it is a fundamental preposition principle in the act of reproduction that there should be, perhaps at very wide intervals, the occasional concourse of two distinct individuals.—On the other hand, I think it must be admitted that greater changes of condition, or more strictly changes of a particular nature with respect to each species, have an special tendency, in both plant animals & plants, to cause infertility, that the cause seems to us to act most capriciously, affecting

(U)

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one order far more than another; but with numerous exceptions in each order. That as slight changes of condition in & slight crosses are good to the individual & as the offspring of the crossing of closely allied forms are more vigorous & fertile so we have a parallel series, in greater changes of condition causing more or less sterility in the individual & in the notorious fact of the lessened fertility or utter sterility in the hybrids produced by the crossing of distinct species or unlike forms. Neither in hybrids, or in an individual species placed out of its natural conditions, can we tell, till we try, whether the fertility will be greatly or slightly affected, so ignorant are we of the precise exact cause. But to the subject of Hybridity we shall hereafter to return.— (U)

(Hence I cannot doubt the truth of the propositions that the condition of existence in all living beings the reproductive system is acted on in an especial manner, unlike any other part of the organisation, by the conditions of existence; that both male & female element is acted on, the action be appearing to us most capricious either for good or evil. This proposition seems to me important, for it brings into connection all the facts in this chapter with the variability of organic beings when placed out of their natural conditions under domestication. If the reproductive system is so easily acted on, that

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changes of condition, which do not in the least affect the health of the individual, yet will seriously affect or entirely stop its function; surely it is not surprising that the product of the reproductive [Stauffer ends here.]

system should be affected; should depart from its normal functions, of that like should produceing like, but that variety should arise, (a) It supports, also, the conclusion to which seemed in the last chapter most probable that the chief cause of variation did not lie superance, in accordance with the common view during frequency, or the in is formation of the seed, or during in the act of impregnation; but in that separate male & female element acted on during the the life of either the or both parents, on the separate male & female elements of reproduction.

(U)