114 CONDITIONS AFFECTING THE 



that you see there is abundant evidence of variation 

 among men in their natural condition. And if you 

 turn to other animals there is just the same thing. The 

 fox, for example, which has a very large geographical 

 distribution all over Europe, and parts of Asia, and on 

 the American Continent, varies greatly. There are 

 mostly large foxes in the North, and smaller ones in 

 the South. In Germany alone, the foresters reckon 

 some eight different sorts. 



Of the tiger, no one supposes that there is more than 

 one species; they extend from the hottest parts of 

 Bengal, into the dry, cold, bitter steppes of Siberia, 

 into a latitude of 50°, — so that they may even prey 

 upon the reindeer. These tigers have exceedingly dif- 

 ferent characteristics, but still they all keep their gen- 

 eral features, so that there is no doubt as to their being 

 tigers. The Siberian tiger has a thick fur, a small 

 mane, and a longitudinal stripe down the back, while 

 the tigers of Java and Sumatra differ in many impor- 

 tant respects from the tigers of Northern Asia. So 

 lions vary ; so birds vary ; and so, if you go further 

 back and lower down in creation, you find fishes vary. 

 In different streams, in the same country even, you 

 will find the trout to be quite different to each other 

 and easily recognizable by those who fish in the par- 

 ticular streams. There is the same differences in 

 leeches ; leech collectors can easily point out to you 

 the differences and the peculiarities which you your- 

 self would probably pass by ; so with fresh-water mus- 

 sels ; so, in fact, with every animal you can mention. 



In plants there is the same kind of variation. Take 

 such a case even as the common bramble. The bota- 

 nists are all at war about it ; some of them wanting to 



