CHAPTEE VIII 



SELECTION 



VAEIATIONS arise by some of the methods just 

 described ; but if the individuals bearing these varia- 

 tions were exposed to free intercrossing with other 

 individuals, the variations would be lost. How are 

 they preserved? 



In the first place , they must be transmitted to the 

 next generation ; and we know from the experience 

 of breeders that at first this transmission is very 

 uncertain ; but becomes more and more certain ac- 

 cording to the number of generations through which 

 they have passed. In time every new race breeds 

 true. Characters which have been acquired through 

 physiogenesis, and which are called acquired charac- 

 ters, do not seem capable of transmission ; but there 

 is much diversity of opinion on this subject among 

 biologists. 



Lamarck assumed that variations arising through 

 physiogenesis, or from use and disuse, would be 

 transmitted to future generations. Several authors 

 have produced much evidence to substantiate this 

 view ; but a large part of it has been shewn to be 

 of no value ; for the facts can be better explained by 



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