Le Dantec 269 



a + Q = X a + R (where a = mass of each single 

 specific assimilating substance; Q = mass of the nutritive 

 substances absorbed ; x = coefficient > i ; and R = mass 

 of the substances of refuse), multiplies all these sub- 

 stances and preserves to them their original proportions. 

 Destruction however, or at least certain destructions, act 

 separately on each of these substances and alter the pro- 

 portions of the mixture and consequently the characters 

 of the plastid." 203 



From this it appears that LeDantec attributes all 

 variations which the plastids or organisms in general 

 can undergo, to total or partial destructions of the dif- 

 ferent, particular plastic substances (a) already present, 

 but never to the production of new plastic substances. 

 The numbers and characters of plastic substances, which 

 participate in the formation of the complex substance 

 of the plastid or rather of the organism in general, may 

 be different in different species. The difference between 

 different species and between different individuals of the 

 same species, would consist only in the proportions in 

 which the special plastic substances (a) peculiar to this 

 species, are united. 



"We are inclined to regard the living substances of 

 the plastids as mixtures of different plastic substances, 

 the substances (a). The species of the plastids would 

 be determined by the nature or quality of these plastic 

 substances; their individual peculiarities, their person- 

 ality, would depend upon the proportions of the mixture of 

 these specific plastic substances. In the same way we must 

 regard the individual substances in the higher organisms 

 as characterized by a mixture in definite proportions of 



lfi Le Dantec: Traite de Biologic. P. 93. 



