42 HEREDITY AND SELECTION IN SOCIOLOGY 



whicli there proceed in the long run the blood-vessels, or the 

 tendons, or the nerves of an organ, need not necessarily be 

 determined in such a fashion that they contain in potentia all 

 the elements of the blood-vessel, or the sinew, or the nerve. 

 It may well happen that the embryonic cell possesses nothing 

 more than a general tendency to determine a given morpho- 

 logical determinate ; while the shape and structure of this deter- 

 minate depends on the environment in which, in each specific 

 case, it may find itself. For instance, we find nerves and blood- 

 vessels located in certain pathological tumours, which were 

 certainly not originally determined in the form in which we see 

 them ; they have been produced by the pressure and specific 

 attraction of the pathological basis which underlies the tumour ; 

 and their original determinants simply possessed the property of 

 producing, under certain circumstances, blood-vessels or nerves 

 in general. 



These preliminary remarks are intended to show that the 

 theory of the " predestination " of the organism in the germ- 

 plasm is not to be confounded with the old theory of " preforma- 

 tion" associated with the name of Bonnet. Epigenesis is not 

 by any means irreconcilable with the doctrine of the germ- 

 plasm. Weismann has merely, if we understand him rightly, 

 gone behind the theory of Woffi. The organism in its finished 

 state is certainly the result of epigenetic development, of a series 

 of successive developmental stages emerging from the primitive 

 germ-cell. But the germ-plasm contains in itself the predis- 

 positions of all the parts of the finished organism ; it contains, 

 not the miniature picture of which a given organ is the enlarged 

 result, but a mass of determinants which possess the property, 

 in conjunction with the given elements of the different cells, 

 of determining the structure and existence of the several parts 

 which go to make up the organism. The theory of determinants 

 is more readily adapted to the facts than the theory of a homo- 



