Origin of Species Variorum

↑ 1 blocks not present in 1872; present in 1859 1860 1861 1866 1869

AS this whole volume is one long argument, it may be convenient to the reader to have the leading facts and inferences briefly recapitulated.

→ variation and natural 1872

natural 1859 1860 1861 1866 1869

→ all parts of the organisation 1869 1872

gradations in the perfection of any organ or instinct, which we may consider, either do now exist or could have existed, each good of its kind,— that all organs 1859

gradations in the perfection of any organ or instinct which we may consider, either do now exist or could have existed, each good of its kind,— that all organs 1860

all organs 1861 1866

→ offer, at least, individual differences— 1869 1872

are, in ever so slight a degree, variable,— and, lastly, 1859 1860

are, in ever so slight a degree, variable— 1861 1866

→ instinct— and, lastly, that gradations in the state of perfection of each organ may have existed, each good of its kind. 1869 1872

instinct. 1859 1860

instinct— and, lastly, that gradations in the perfection of every organ may have existed, each good of its kind. 1861 1866

→ which have suffered much extinction; but 1861 1866 1869 1872

but 1859 1860

→ OMIT 1860 1861 1866 1869 1872

as is proclaimed by the canon, "Natura non facit saltum," 1859

CHAPTER

XIV.

XV.

RECAPITULATION AND CONCLUSION.

Recapitulation of the

difficulties on

objections to

the theory of Natural Selection— Recapitulation of the general and special circumstances in its

favour.—

favour—

Causes of the general belief in the immutability of species— How far the theory of

natural

Natural

selection

Selection

may be extended— Effects of its adoption on the study of Natural

history—

History—

Concluding remarks. ↑

That many and

grave

serious

objections may be advanced against the theory of descent with modification through →variation and natural selection, I do not deny. I have endeavoured to give to them their full force. Nothing at first can appear more difficult to believe than that the more complex organs and instincts

should

....

have been perfected, not by means superior to, though analogous with, human reason, but by the accumulation of innumerable slight variations, each good for the individual possessor. Nevertheless, this difficulty, though appearing to our imagination insuperably great, cannot be considered real if we admit the following propositions,

namely,—

namely,

that →all parts of the organisation and instincts →offer, at least, individual differences— that there is a struggle for existence leading to the preservation of

each

....

profitable

deviation

deviations

of structure or →instinct— and, lastly, that gradations in the state of perfection of each organ may have existed, each good of its kind. The truth of these propositions cannot, I think, be disputed.

It is, no doubt, extremely difficult even to conjecture by what gradations many structures have been perfected, more especially amongst broken and failing groups of organic

beings;

beings,

→which have suffered much extinction; but we see so many strange gradations in nature, →OMIT that we ought to be extremely cautious in saying that any organ or instinct, or

the

any

whole

being,

structure,

could not have arrived at its present state by many graduated steps. There are, it must be admitted, cases of special difficulty

opposed to

the theory of natural selection; and one of the most curious of these is