16 



SOCIAL EVOLUTION 



Mendel's theory like Weismann's has the idea of ger- 

 minal continuity for one of its foundations. It conceives 

 of the hereditary relation as one between the parental 

 and filial germ cells and not between the bodies of parent 



RED 



WHITE 



FIGURE 6. Mendelian Inheritance in Four-o'clocks. 



and offspring. Mendelism explains the organism as 

 built up of a number of definite and separably inheritable 

 characters. Variation seems to consist in the presence 

 or omission of elementary factors. Thus, the white sweet 

 pea was brought about in the variation by which one of 

 the color factors was dropped out. Variation is not 

 always the progression from a lower degree of com- 



