312 Explanation of Inheritance 



polation, quite analogous to that of which we have 

 spoken above, of three or more groups of specific poten- 

 tial elements in the whole series of germinal elements, 

 with the result that the activation of one of these groups 

 prevents that of all the others. Thus each form of the 

 polymorphous kind would have its own characters which 

 arise entirely by the inheritance of characters acquired 

 through functional adaptation. 



It is nevertheless to be remarked that a few forms 

 of certain polymorphous species are possibly to be 

 ascribed also to the circumstance that a few groups 

 among all the specific potential germinal elements of the 

 entire series are hindered in their activation, not so much 

 by properly ontogenetic conditions which depend upon 

 the development of other characters, as rather by quite 

 general conditions of temperature, nutrition, etc., so that 

 thus the form in which .hese groups are not activated, 

 differs from the principal form only through the absence 

 of some single character. This might be the case, for 

 example, in the working bees and generally in the neuters 

 of many insects, the explanation of which would thus 

 be quite similar to that which Spencer gives in his polemic 

 with Weismann. But evidently these forms with incom- 

 plete development represent essentially only a special case 

 of the preceding supposition. 



We can thus say also that the fundamental principle 

 to which centroepigenesis has recourse in order to explain 

 sexual dimorphism and polymorphism in general, that 

 is, to explain how it comes about that the development 

 of certain characters prevents that of certain others 

 which remain latent, is still the same principle which 

 has already served to explain the fact that ontogenetic 



