Origin of Species Variorum

→ and that there must be some error in all the foregoing remarks, 1859 1860 1861 1866

OMIT 1869 1872

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

With some exceptions, presently to be given, I fully admit that this is the rule.

→ I fully admit that this is almost invariably the case. 1859 1860

But the subject is surrounded by difficulties, for, looking to varieties, produced under nature, if two forms hitherto reputed to be varieties be found in any degree sterile together, they are at once ranked by most naturalists as species. 1869

→ if we look 1859 1860

the subject is surrounded by difficulties, for looking 1861

the subject is surrounded by difficulties, for, looking 1866 1872

→ we are immediately involved in hopeless difficulties; for 1859 1860

OMIT 1861 1866 1872

→ hitherto reputed 1859 1860

forms hitherto reputed to be 1861 1866 1872

→ the primrose and cowslip, 1859 1860 1861

OMIT 1866 1869 1872

→ many of our best 1859 1860 1861

most 1866 1869 1872

→ the German Spitz dog unites more easily than other dogs with foxes, or that 1859 1860 1861

the German Spitz dog crosses more easily with the fox than do other dogs, or that 1866 1869

OMIT 1872

→ these dogs have 1859 1860 1861 1866

these dogs are 1869

they are 1872

that there must be some essential distinction between species and varieties, →and that there must be some error in all the foregoing remarks, inasmuch as

the latter,

varieties,

however much they may differ from each other in external appearance, cross with perfect facility, and yield perfectly fertile offspring. ↑ →I fully admit that this is almost invariably the case. But →if we look to varieties produced under nature, →we are immediately involved in hopeless difficulties; for if two →hitherto reputed varieties be found in any degree sterile together, they are at once ranked by most naturalists as species. For instance, the blue and red pimpernel, →the primrose and cowslip, which are considered by →many of our best botanists as varieties, are said by Gärtner

~~not~~

not

to be quite

sterile

fertile

when crossed, and he consequently ranks them as undoubted species. If we thus argue in a circle, the fertility of all varieties produced under nature will assuredly have to be granted.

If we turn to varieties, produced, or supposed to have been produced, under domestication, we are still

in- volved

involved

some doubt.

doubt.

For when it is stated, for instance, that →the German Spitz dog unites more easily than other dogs with foxes, or that certain South American indigenous domestic dogs do not readily

unite

cross

with European dogs, the explanation which will occur to every one, and probably the true one, is that →these dogs have descended from

~~several~~

several

aboriginally distinct species. Nevertheless the perfect fertility of so many domestic

races,

varieties,

differing widely from each other in appearance, for instance

those of

the

pigeon,

pigeon

the cabbage, is a remarkable fact; more especially when we reflect how many species there are, which, though resembling each other most closely, are utterly sterile when intercrossed. Several considerations, however, render

this

the

fertility of domestic varieties less

remarkable.

remarkable

~~than~~

than