i8 INTERNAL SECRETIONS 



some sexual characters, as for instance, the penis, the beard, 

 and the sexual libido can continue their development to a 

 certain degree after prepuberal castration. And after post- 

 puberal castration the sexual characters, both physical and 

 psychical, persist to some extent. So the sexual characters 

 are in a certain degree independent of the sexual gland, and the 

 influence of the latter on the former may be understood as of 

 the nature merely of a "protection " necessary for the develop- 

 ment of the sexual characters. This view was put forward 

 notably by Halhan (1903). But on the other hand we must not 

 forget that castration, even when done as early as possible, is 

 always performed on an organism with sexual characters 

 already partly developed, and we cannot exclude the possi- 

 biUty that the sexual glands before removal were already able 

 to fix, in a sexual sense, the embryonic soma. Thus the fact 

 that some sexual characters persist after castration is no real 

 evidence against the conception of an asexual stage in the 

 ontogenetic development of the soma. 



But we must confess that the observations made on the 

 castrated man do not supply the proof we would like to have in 

 dealing with the question whether and how far the "castrate" 

 approaches to a type common to both sexes, although it must 

 be said that our conception that every sexually differentiated 

 soma goes through an asexual stage during ontogenetic develop- 

 ment, is not incompatible with the facts observed in man. 

 Now the experimental investigations made with castration in 

 mammals, and still more those in birds, give a very strong 

 support to this conception. We shall see that for birds 

 the existence of a common type after castration is a well- 

 established fact, at least in regard to external appearance. 



B. THE RESULTS OF CASTRATION IN MAMMALS. 

 I. Morphological Signs of Castration. 

 Although castration was performed on mammals, such as 

 on the bull and the horse, even in ancient times, our knowledge 

 of the influence of the sexual glands on the development of the 

 sexual characters of this class was not much advanced thereby. 

 Not until lately have systematic scientific observations been 

 made on the bull and the cow. Important data upon the question 

 as to the results of castration have been obtained from experi- 

 ments made on the rat, guinea pig, rabbit, dog, and hedgehog. 



