322 THE CAUSES OF THE XI 
in the whole continent of America, from Labrador 
down to Cape Horn. This is an empirical fact, and 
it is what is called, stated in the way I have 
given it you, the “ Geographical Distribution ” of 
the horse. 
Why horses should be found in Europe, Asia, 
and Africa, and not in America, is not obvious; 
the explanation that the conditions of life in 
America are unfavourable to their existence, and 
that, therefore, they had not been created there, 
evidently does not apply ; for when the invading 
Spaniards, or our own yeomen farmers, conveyed 
horses to these countries for their own use, they 
were found to thrive well and multiply very 
rapidly ; and many are even now running wild in 
those countries, and in a perfectly natural condition. 
Now, suppose we were to do for every animal 
what we have here done for the horse,—that is, 
to mark off and distinguish the particular district 
or region to which each belonged; and supposing 
we tabulated all these results, that would be 
called the Geographical Distribution of animals: 
while a corresponding study of plants would yield 
as a result the Geographical Distribution on 
plants. 
I pass on from that now, as I merely wished te. 
explain to you what I meant by the use of the 
term “Geographical Distribution.” As I said 
there is another aspect, and. a much more im 
portant one, and that is, the relations of the niall 
