120 CONDITIONS AFFECTING THE 



while the tigers of Java and Sumatra differ in many 

 important 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 particular 

 streams. There is the same differences in leeches ; leech 

 collectors can easily point out to you the differences 

 and the peculiarities which you yourself would pro- 

 bably pass by ; so with fresh-water mussels ; 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 

 make out that there are many species of it, and others 

 maintaining that they are but many varieties of one 

 species j and they cannot settle to this day which is a 

 species and which is a variety ! 



So that there can be no doubt whatsoever that any 

 plant and any animal may vary in nature ; that varieties 

 may arise in the way I have described, — as spontaneous 

 varieties, — and that those varieties may be perpetuated 

 in the same way that I have shown you spontaneous 

 varieties are perpetuated; I say, therefore, that there 

 can be no doubt]|as to the origin and perpetuation of 

 varieties in nature. 



But the question now is: — Does selection take 

 place in nature? is there anything like the operation 

 of man in exercising selective bi-eeding, taking place 

 in nature? You will observe that, at present, I say 

 nothing about species ; I wish to confine myself to the 



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