1892.] on Micro-organisms in their Belation to Chemical Change. 633 



This power of modifying tlie characters of bacteria by cultivation 

 is, I venture to think, of the highest importance in connection with 

 the problems of evolution, for in these lowly forms of life in which, 

 under favourable circumstances, generation succeeds generation in a 

 period of as little as 20 minutes, it should be possible through the 

 agency of selection to effect metamorphoses, both of morphology 

 and physiology, which would take ages in the case of more highly 

 organised beings to bring about. 



We hear much about the possibility of altering the human race 

 through training from the enthusiastic apostles of education, but 

 even the most sanguine cannot promise that any striking changes 

 will be effected within several generations, so that such predictions 

 cannot be tested until long after these reformers have passed away. 

 In the case of micro-organisms, however, we can study the effect 

 of educational systems consequentially pursued through thousands 

 of generations within even that short span of life which is allotted to 

 us here. 



[P. F. F.] 



