322 THE CAUSES OF THE X l 



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 of 

 plants. 



I pass on from that now, as I merely wished to 

 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 various 



