Chap. I, 
UNDEE DOMESTICATION. 
17 
offspring of any single species, then such facts would have 
great weight in making us doubt about the immutability 
of the many very closely allied natural species—for in¬ 
stance, of the many foxes—inhabiting different quarters 
of the world. I do not believe, as we shall presently 
see, that 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 being descended from distinct 
species. In the case of some other domesticated species, 
there is presumptive, or even strong evidence, that all 
the breeds have descended from a single wild stock. 
It has often been assumed that man has chosen for 
domestication animals and plants having an extra¬ 
ordinary 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 or guinea-fowl, or the small power of endurance 
of warmth by the reindeer, or of cold by the common 
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 possible to come 
to any definite conclusion, whether they have descended 
from one or several wild species. The argument mainly 
relied on by those who believe in the multiple origin 
