Origin of Species Variorum

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

There can be no doubt that a race may be modified by occasional crosses, if aided by the careful selection of those individual mongrels, which present any desired character; but that a race could be obtained nearly intermediate between two extremely different races or speceies, I can hardly believe.

→ and 1859 1860 1861 1866 1869

in character, and 1872

→ or rather utter hopelessness 1866

or rather utter hopelessness, 1859 1860 1861

OMIT 1869 1872

→ Pigeon, their Differences and Origin . 1866 1869

Pigeon .— 1859 1860 1861

Pigeon , their Differences and Origin . 1872

~~freely~~

freely

in a state of nature? It has often been loosely said that all our races of dogs have been produced by the crossing of a few aboriginal species; but by crossing we can

get only

only get

forms in some degree intermediate between their parents; and if we account for our several domestic races by this process, we must admit the former existence of the most extreme forms, as the Italian greyhound, bloodhound, bull-dog, &c., in the wild state. Moreover, the possibility of making distinct races by crossing has been greatly exaggerated. ↑ Many cases are on record, showing that a race may be modified by occasional crosses, if aided by the careful selection of the individuals which present the desired character; but to obtain a race nearly intermediate between two extremely different races or species, would be very difficult. Sir J. Sebright expressly

experimentised

experimented

with

for

this object, and failed. The offspring from the first cross between two pure breeds is tolerably and sometimes (as I have found with pigeons)

quite

extremely

uniform

uniform,

→and everything seems simple enough; but when these mongrels are crossed one with another for several generations, hardly two of them

are

will be

alike,

alike;

and then the

~~extreme~~

extreme

difficulty

difficulty,

→or rather utter hopelessness of the task becomes

manifest.

apparent.

Cer- tainly,

Certainly,

a breed intermediate between two very distinct breeds could not be got without extreme care and long-continued selection; nor can I find a

~~single~~

single

case on record of a permanent race having been thus formed.

On the

....

Breeds of the Domestic → Pigeon, their Differences and Origin .

Believing that it is always best to study some special group, I have, after deliberation, taken up domestic pigeons. I have kept every breed which I could purchase or obtain, and have been most kindly favoured