EIGHTEENTH CENTURY EVOLUTIONISTS 169 



in the parent, and conserve a sort of recollection 

 (souvenir) of their previous form, so that in the off- 

 spring they will reflect and reproduce a resemblance 

 to the'parents. ... If some of the particles happen 

 to be missing, an imperfect being is formed. . . . If 

 the elements of the different species are united, a 

 hybrid is produced. ... In some cases a child re- 

 sembles one of his ancestors more than even its par- 

 ents ; in this case we may suppose that the material 

 particles conserve more strongly the habits they pos- 

 sessed in the ancestral form. 



De Maiipertuis thus gives us an hypothesis 

 which resembles both the 'pangenesis' of Darwin 

 and the 'perigenesis' of Haeckel.^ 



These principles of individual reproduction 

 and of 'reminiscence' heredity enable de Mau- 

 pertuis to explain readily the origm of new spe- 

 cies, and here again we find a striking anticipa- 

 tion of one modern doctrine of the cause of 

 fortuitous variation (section xlv) : 



We can thus readily explain how new species are 

 formed ... by supposing that the elementary par- 

 ticles may not always retain the order which they 

 present in the parents, but may fortuitously produce 

 differences, which, multiplying and accumulating, 

 have resulted in the infinite variety of species which 



1 In Haeckel's Perigenesis of the Plcn'tidules, we have a theory 

 of heredity based upon the assumption that the material heredi- 

 tary particles preserve a power of repetition of former states 

 analogous to that witnessed in memory. 



