THE GEEM-PLASM THEORY 391 



separated into two kinds of ids, so that tlie germ-plasm oi' these 

 species must contain four kinds of ids. 



I might cite many more cases in regard to which the assumption 

 of two or more kinds of determinants seems imperative, but I l)elieve 

 that wdiat has been said is enough to enable any one to think out 

 other cases for himself. 



B b 2 



