See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1860
1861
1866
1869
1872

all our dogs have 1859
the whole amount of difference between the several breeds of the dog has been produced under domestication; I believe that a small part of the difference is due to their being 1872

any one wild species; but, in the case of some other domestic races, there is presumptive, or even strong, evidence in favour of this view. 1859
distinct species. 1872

1 blocks not present in 1859 1872; present in 1860 1861 1866 1869
the whole amount of difference between the several breeds of the dog has been produced under domestication; I believe that some small part of the difference is due to their having descended from distinct species.

vary on an average 1859 1860 1861
on an average vary 1866 1869 1872

I do not think 1859 1860
OMIT 1861 1866 1869 1872

bloodhound, terrier, spaniel, and bull-dog, which we all know propagate their kind
so
so
truly, were the offspring of any single species, then such facts would have great weight in making us doubt about the immutability of the many
very
very
closely allied
and
and
natural species — for instance, of the many foxes — inhabiting different quarters of the world. I do not believe, as we shall presently see, that all our dogs have descended from any one wild species; but, in the case of some other domestic races, there is presumptive, or even strong, evidence in favour of this view.
It has often been assumed that man has chosen for domestication animals and plants having an extraordinary inherent tendency to vary, and likewise to withstand diverse climates. I do not dispute that these capacities have added largely to the value of most of our domesticated productions; but how could a savage possibly know, when he first tamed an animal, whether it would vary in succeeding generations, and whether it would endure other climates? Has the little variability of the ass
and goose,
or guinea-fowl,
or the small power of endurance of warmth by the
reindeer,
rein-deer,
or of cold by the common
camel
camel,
prevented their domestication? I cannot doubt that if other animals and plants, equal in number to our domesticated productions, and belonging to equally diverse classes and countries, were taken from a state of nature, and could be made to breed for an equal number of generations under domestication, they would vary on an average as largely as the parent species of our existing domesticated productions have varied.
In the case of most of our anciently domesticated animals and plants, I do not think it is
not possible
possible
to come to any definite conclusion, whether they
are
have
descended from one or several
wild species.
species.
The argument mainly relied on by those who believe in the multiple origin