THE GENERATIVE GLANDS 359 



to disprove such dependence. Such are the cases of double con- 

 genital agenesis of the genital glands, with complete development 

 of the external and internal sexual organs. 



Interesting cases of hermaphroditic malformation have been 

 observed in animals. Kolliker describes a pig 15 months old, 

 which had well-developed testes, shrivelled seminal vesicles and 

 Cowper's glands, and a large uterus with two cornua. v. la 

 Valette St. George describes the findings in a striped water-newt 

 (Triton tccniatus) as follows : Testicles and male secondary sexual 

 stigmata, large ovaries but no oviduct. Gerhartz observed a 

 Rana esculenta with proponderating male characteristics, which 

 also possessed a well-formed oviduct, but had no ovaries nor 

 were eggs present in the testes. These observations show that 

 the secondary genital organs are not only not derived from the 

 same primitive beginning as the genital glands, but that their 

 further development also is sometimes independent of the latter. 

 There are certain exceptions to the rule that the sexual character 

 of the secondary organs is in accordance with that of the genital 

 glands. 



In addition to the differentiated genital organs, which form 

 the primary stigmata of sex, there are other phenomena by which 

 the sexes are characterized. J. Hunter described these as 

 " secondary sexual characteristics " and includes under this head- 

 ing all the specific appearances which are not directly concerned 

 with the processes of reproduction. It is true, as Darwin pointed 

 out, that this definition is a loose one, for it is extremely difficult 

 to decide in individual cases whether a detail of structure or of 

 function is concerned with reproduction or not. 



The term " secondary sexual characteristics ' is inexact for 

 another reason, namely, that it suggests a dependence of these 

 characteristics upon the genital glands, and of this we have at 

 present no proof. As we have shown in dealing with the 

 secondary genital organs, such proof is difficult to obtain. 



The only justifiable grounds for distinction is the differentia- 

 tion between the cells of generation and the other somatic cells, 

 which is manifested in their biological behaviour. The somatic 

 cells are independent and capable of fission, but they are transitory 

 structures. The cells of generation, on the other hand, are not 

 autonomous, but they possess the capacity of forming another 

 individual after their nuclear portion has combined with that of 

 cells of the opposite sex. 



Thus in all organisms with a sexual digenetic method of re- 

 production, there are two types of biologically incomplete cells 

 of generation, the male and the female, and these only attain 

 completion by means of the process of fertilization. 



The somatic cells are completely autonomous, and a bio- 

 logical differentiation, such as that which characterizes the cells of 

 generation, is superfluous to their development; sexual dimor- 



