4o8 INTERNAL SECRETIONS 



in man completely resembling one another.^ This is why I 

 should Hke to emphasize that a classification of cases of inter- 

 sexuality according to sex characters, though very useful for 

 orientation in this field, will not help in further research, if 

 general morphogenetic factors with their time and quantitative 

 relations are not taken into consideration. No doubt, for the 

 moment it is not possible to build up definitely the theory of 

 intersexuality in mammals and birds on an hormonic basis. 

 But on the other hand it cannot be denied that an extra- 

 ordinary progress has been made in this field since Steinach 

 began his experiments with feminization and masculinization,. 

 i.e., since investigators began to work in this field on an 

 hormonic basis. There are a great number of different 

 problems concerning intersexuality which might be explained 

 on this basis, especially if time relations and quantitative 

 relations are considered. An example may be given. Hirsch- 

 feld writes (1918, p. 103) : " Is the great variability of symptoms 

 in intersexuality due to the reaction of the breasts, or the larynx, 

 or other parts involved being different in individual cases, 

 or is it due, as it seems to me probable, to a specific composition 

 of the sexual hormones, the chemical formula of which must be 

 surely a very complex one?" It cannot be denied that the 

 development of different normal sex characters at different 

 times could be caused by the sexual hormones produced at 

 different stages of individual development being different from 

 one another. But if we adopt Hirschfeld's standpoint in ex- 

 plaining the enormous variability of symptoms in intersexuality 

 we must assume that there is an enormous variabiHty in the 

 quality of the sexual hormones. But nothing is thereby reaUy 

 accounted for, one unknown factor being replaced by another. I 

 am rather of the opinion that the question can be decided best 

 on the assumption that the different parts of the organism 

 react differently to the hormones, and that their reaction 

 varies with age. 



There is one fact, however, which does not conform with the 



^ A very striking example of how the time factor interferes in intersexuality^ 

 causing an extraordinary variability, is given by observations of Goodale, 

 (1916 b) on feathers of castrated fowls which were moulting at the time of the- 

 operation. " Individual feathers from such breeds often show both male and 

 female colors, color patterns, and even shapes, the area occupied by each 

 depending upon the age of the feather germs..." Lately special attention 

 has been given to this question by Pezard, Sand, and Caridroit (1923 b^ 

 1923 c) who experimented on engrafted fowl. 



