296 EVOLUTION IN BIOLOGY. 



influenced the female organism as a contagion ; and that 

 the blood, which he conceived to be the first rudiment 

 of the germ, arose in the clear fluid of the " colliquamen- 

 tum " of the ovum by a process of concrescence, as a sort 

 of living precipitate. We now know, on the contrary, 

 that the female germ or ovum, in all the higher animals 

 and plants, is a body which possesses the structure of a 

 nucleated cell ; that impregnation consists in the fusion 

 of the substance * of another more or less modified nu- 

 cleated cell, the male germ, with the ovum; and that 

 the structural components of the body of the embryo 

 are all derived, by a process of division, from the coa- 

 lesced male and female germs. Hence it is conceivable, 

 and indeed probable, that every part of the adult con- 

 tains molecules, derived both from the male and from 

 the female parent ; and that, regarded as a mass of mo- 

 lecules, the entire organism may be compared to a web 

 of which the warp is derived from the female and the 

 woof from the male. And each of these may constitute 

 one individuality, in the same sense as the whole organ- 

 ism is one individual, although the matter of the organ- 

 ism has been constantly changing. The primitive male 

 and female molecules may play the part of Buffon's 

 "moules organiques," and mould the assimilated nutri- 

 ment, each according to its own type, into innumerable 

 new molecules. From this point of view the process, 

 which, in its superficial aspect, is epigenesis, appears in 

 essence, to be evolution, in the modified sense adopted 



* Not yet actually demonstrated in the case of phoenogamous plants. 



