358 THE GERM-PL.ASM 



been present in a latent condition in an entire series of female 

 generations. 



The germ-plasm of the fertilised egg-cell must therefore 

 contain the primary constituents of all the secondary male and 

 female sexual characters, as well as those of the male and female 

 germ-cells. We might, then, suppose that this would be 

 accounted for by the assumption that the determinants of both 

 kinds of characters are contained in the germ-plasm, and that 

 the decision as to sex is not only determined with regard to the 

 sexual determinants, — so that the germ-cells take on a male or a 

 female character, — but also as regards the somatic determinants, 

 in order that the secondary se.xual character of the male or of 

 the female may take the lead in the building up of the body. 



This assumption is certainly indispensable, and it sufBces as 

 far as the latent transference of secondary characters of both 

 kinds from the germ-plasm of one generation to that of the 

 next is concerned, but it still requires an essential addition. 

 A number of facts indicate that the latent primary constituents 

 of secondary characters of both kinds are not only present in 

 the germ-plasm from which the organism arises, but also in the 

 fully developed body of the organism. Tlie fact that the char- 

 acters of both sexes can be transmitted to descendants, proves 

 that the germ-plasm must contain the corresponding primary 

 constituents of both ; and in the sixth chapter it has already 

 been shown how this transmission may be accounted for by a 

 continuity of the germ-plasm from one generation of germ-cells 

 to the next. We are now concerned with the fact that m.ature 

 individuals may also contain the primary constituents of sec- 

 ondary sexual characters of both kinds, and that those of the 

 female may be present in the body as well as in the germ-cells 

 of a male organism, and conversely those of the male may e.xist 

 in the female. The well-known facts to which I refer have 

 been carefully collected and fully discussed by Darwin, and are 

 briefly as follows : — the Secondary sexual characters of one 

 sex may. under special circumstances, become developed sub- 

 sequently in fully-developed individuals. Tliis results in both 

 sexes, especially in the case of castration. The removal of the 

 sexual '■ glands ' from young mammals and birds prevents the 

 development of secondary male sexual characters. Castrated 

 cocks, for example, retain the appearance of hens, and do not 

 develop the beautiful tail or the large comb and spurs of the 



