THE BIOGENETIC LAW 191 



variation in all the rest of the parts and stages of the animal. 

 A theory of epigenesis cannot do this, for, if no representative 

 particles were contained in the germ-plasm, then every variation of 

 it would affect the whole course of development and every part of the 

 organism, and variations of individual parts arising from the germ 

 would be impossible. 



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