310 Explanation of Inheritance 



centroepigenesis is able to account for the inheritance of 

 acquired characters in general, the particular case of this 

 inheritance, constituted by sexual dimorphism and by 

 polymorphism in general, which up till now we have 

 been compelled to leave aside, becomes explained at once. 



The question of primary and secondary sexual char- 

 acters, writes Delage, is connected with one of the most 

 important questions of general biology : "When one 

 part develops in a certain way another part develops 

 correlatively in a certain way, and if the first had devel- 

 oped in another way, the development of the second 

 would also have been different; and this although no 

 direct connection exists between these two parts. The 

 question presents itself also in the following way: In 

 what way and under what form can this reciprocal 

 influence of the organs acting at a distance be effected 

 without any similarity between cause and effect?" 229 



The explanation which the centroepigenetic hypothesis 

 can afford for sexual dimorphism is the following : It is 

 due to the fact that in the whole series of germinal specific 

 potential elements there are found interpolated two dis- 

 tinct groups of these elements, such that the activation 

 by the central zone of one of these groups would pre- 

 clude the activation of the other and vice versa. Then as 

 soon as the two sexes have commenced to differ somat- 

 ically even a very little from each other, every later 

 sexual character, whether principal or secondary, acquired 

 by functional adaptation by the male or female, or better 

 the entire conformation of the whole organism resulting 

 therefrom, would become represented in the central zone 

 of that organism by a corresponding small group of 



229 Delage: L'heredite etc. P. 184185. 



