RETROGRESSION. 105 



speculations, is very different from a conflict 

 between the molecules themselves ; for in 

 this case we might expect the frequent ap- 

 pearance of animals with diminished organs, 

 and others with theirs enlarged. 



The hypothesis is developed by Professor 

 Weissman in his ' Germinal,' where he re- 

 cognises that neither natural selection nor 

 varying external conditions of existence will 

 wholly account for degradation. 



" Germ-plasm," he says, " must be altered 

 the whole vital particles of which it is 

 composed " ; and again, " Neither natural 

 selection nor varying differences of life will 

 wholly account for variation, which is com- 

 pleted by profound processes of selection 

 in the germ-plasm." 



This he calls " Germinal Selection." 



The necessary modification is brought 

 about by what Professor Weissman calls 

 " determinants," " that appropriate nourish- 

 ment in the germ-plasm for the particular 

 organs they produce each battles stoutly 

 for its food, the stronger appropriates part 

 of the share of the weaker neighbours, who 

 ultimately disappear, and with them the 

 part of the organism they represent." 



Applying this doctrine to the case of the 

 snake, the " determinants " of the organs of 



