PACTS 203 



pendent that, in the course of the individual life, certain 

 quantitative variations of this hereditary patrimony become 

 possible under the influence of functional assimilation. 

 These distinct elements are perhaps diastases, perhaps 

 chemically-defined substances, perhaps both at the same 

 time. When we wish to reason without compromising the 

 future, we had best represent them by letters without pre- 

 tending to know anything more about them. 



We represent by our symbols A l5 A 2 , . . . A B , the successive 

 forms of an individual under development. If the develop- 

 ment takes place under conditions favourable to the species, 

 in conditions in which the species has lived for long genera- 

 tions and to which it is habituated, we may consider that the 

 hereditary patrimony a of the egg is transmitted integrally 

 to the individuals A t , A 2 , . . . A n . But it is more likely, 

 and more of a generalization, to suppose that the hereditary 

 patrimony a of the egg undergoes in the course of successive 

 functional assimilations quantitative variations. Accord- 

 ingly we say that, to the successive forms A l5 A 2 , A 3 . . . A n , 

 there correspond hereditary patrimonies a L , a 2 . . . a n . In 

 this way we shall not separate the question of heredity in the 

 strict and rigorous sense from the far vaster and more 

 general question of the heredity of acquired characters. Here- 

 dity without any modification of the hereditary patrimony 

 transmitted from parent to child is only a particular and 

 restricted case of the really general heredity of acquired 

 characters. 



