Origin of Species Variorum

→ seems to me 1859 1860

seems 1861 1866

which was first propounded by Pallas, seems 1869

which was first propounded by Pallas, seems by far 1872

→ I am inclined to believe in its truth, although it rests on no direct evidence. 1859 1860 1861

I have hardly any doubt of its truth, although it rests on no direct evidence. 1866

can, indeed, hardly be doubted. 1869 1872

→ that 1859 1860 1861

almost certain that 1866 1869 1872

→ there is reason to believe that our European and the humped Indian 1859 1860 1861

I have lately acquired decisive evidence that the crossed offspring from the Indian humped and common 1866 1869 1872

→ quite fertile together; but from facts communicated to me 1859 1860 1861

inter se perfectly fertile; and from the observations by Rütimeyer on their important osteological differences, as well as from those 1866 1869

inter se perfectly fertile; and from the observations by Rütimeyer on their important osteological differences, as well as from those 1872

→ I think they 1859 1860 1861

on their differences in habits, voice, constitution, &c., these two forms 1866 1869 1872

→ distinct species. 1859 1860 1861

good and distinct species—as good as any in the world. 1866

good and distinct species as any in the world. 1869

good and distinct species. 1872

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

The same remarks may be extended to the two chief races of the pig.

→ On this view 1859 1860 1861 1866

According to this view 1869

We must, therefore, either give up the belief 1872

→ origin of many of our domestic animals, 1859 1860 1861 1866

origin of many domestic animals, 1869

universal sterility of species when crossed; or 1872

→ either give up the belief of the almost universal sterility of distinct species of animals when crossed; or we must 1859 1860 1861 1866 1869

OMIT 1872

→ sterility, 1859 1860 1861 1866 1869

this sterility in animals, 1872

largely accepted by modern naturalists; namely, that most of our domestic animals have descended from two or more

wild

aboriginal

species, since commingled by intercrossing. On this view, the aboriginal species must either at first have produced quite fertile hybrids, or the hybrids must have become in subsequent

generation

generations

quite fertile under domestication. This latter

alternative,

alternative

→seems to me the most probable, and →I am inclined to believe in its truth, although it rests on no direct evidence.

It is,

I believe,

for instance, →that our dogs

are

have

descended from several wild stocks; yet, with perhaps the exception of certain indigenous domestic dogs of South America, all are quite fertile together;

but

and

analogy makes me greatly doubt, whether the several aboriginal species would at first have freely bred together and have produced quite fertile hybrids. So again →there is reason to believe that our European and the humped Indian cattle are →quite fertile together; but from facts communicated to me by Mr.

Blyth

Blyth,

→I think they must be

regarded

considered

as →distinct species. ↑ →On this view of the →origin of many of our domestic animals, we must →either give up the belief of the almost universal sterility of distinct species of animals when crossed; or we must look at →sterility, not as an indelible characteristic, but as one capable of being removed by domestication.

Finally,

considering

looking to

all the ascertained facts on the intercrossing of plants and animals, it may be

con- cluded

concluded

that some degree of sterility, both in first crosses and in hybrids, is an extremely general result; but that it cannot, under our present state of knowledge, be considered as absolutely universal.

Laws

governing

the

Sterility

first

Crosses

and

Hybrids .

Hybrids .—

We will now consider a little more in detail the