428 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
a possible explanation, which, as wil] be recalled, did not long sur- 
vive. Weismann offered in explanation his germinal selection, which 
was soon discarded because it was beyond the possibility of experi- 
mental testing. Aside from these two attempts to explain individual 
variation no other comprehensive scheme had been presented. Biolo- 
gists had simply recognized the fact of individual] variation without 
any conception of the mechanism. They knew that individual varia- 
tion existed but had even stopped asking why it existed. 
The importance of this new theory, therefore, is obvious. It is 
an ingenious explanation of the inheritance of quantitative characters 
and of the existence of individual variations. Furthermore, the theory 
has not been developed through meditation, but has its basis in 
scientific experiments. It is imaginative toa certain extent, of course, 
as is every other valuable theory, but unlike most such theories it has 
a substantial foundation, namely, Mendel’s law. 
