404 INTERNAL SECRETIONS 



either by the sex gland or, as some authors suppose, by other 

 organs of internal secretion. It would appear also that the 

 generative cells may be dependent upon sexual hormones,, 

 since the sex of the gonad can be experimentally induced or 

 changed by hormonic action. If we imply by the notion 

 "secondary" sex characters some kind of genetic hormonic 

 dependence, the gonads of mammals and birds, in the light of 

 Willier's and Minoura's work, are themselves secondary sex 

 characters conditioned by sexual hormones! 



Though I hold that it is not possible to demonstrate that all 

 cases of intersexuality in mammals and birds are caused by an 

 intersexuality in hormone-production, I think it should be of 

 great interest to attempt a classification of intersexuahty based 

 on that assumption. It may well serve as a working hypothesis. 

 But such a classification cannot yet be made very satisfactorily, 

 our knowledge of the morphogenetic role of the sex hormones 

 in somatic and psychical intersexuality being still very in- 

 complete and of a more general order. We suppose that male 

 and female sexual hormones circulate sometimes simul- 

 taneously, sometimes successively in the same individual. We 

 may also suppose that abnormal hormone-production often 

 takes place only during embryonic development, whereas seem- 

 ingly in the same individual during extrauterine life the pro- 

 duction of hormones is only of one sex. But in such cases 

 there will be a somatic intersexuality during the whole of life 

 as some sex characters are already fixed during embryonic 

 development. Further, if there is in an adult a successive 

 production of hormones of two sexes, a periodic change of some 

 sex characters might take place; this change will concern, 

 especially those characters which have retained a certain 

 growth intensity and plasticity, as, for instance, the hair or the 

 mammary glands, or such organs as are of great lability like 

 the central nervous system. 



It is clear that such a classification cannot be based on direct 

 clinical observation, but only on deduction from what we 

 know concerning experimentally produced intersexuality. 

 The use of such a classification would rather be to present a 

 general view of the enormous variability shown by cases of 

 intersexuality, and to provide a w^orking hypothesis for further 

 research. But such a classification will not serve our purpose, 

 if we require a better designation of individual cases of 



