84 INTERNAL SECRETIONS 



Steinach relates having observed in some of his experi- 

 ments an underdevelopment of the sexual characters ; in these 

 cases the testicular grafts were small. He concluded from 

 these observations that there is a correspondence between the 

 degree of maleness and the quantity of testicular mass in the 

 animal. But I think that this conclusion is not justified, since 

 complete maleness is possible even when the testicular fragment 

 is extremely small, as in partial castration (Pezard, 1918 ; 

 Lipschutz and co-workers, 1920 and 1921). I am inclined to 

 beheve rather that the underdevelopment of the sex characters 

 in some of these experiments was caused by the underdevelop- 

 ment of the testicles. In Chapter IV. we shall discuss more 

 fully our own experiments, in which we were able to show 

 that, by manipulating the testicle of a young animal, develop- 

 ment of the organ and of the sex characters can be 

 retarded, although finally normal maleness may be attained. 



As to the psycho-sexual behaviour Steinach relates that 

 some animals Avith a transplanted testicle showed an abnorm- 

 ally intense libido. But I am rather sceptical as to detailed 

 data concerning the intensity of the psycho-sexual behaviour 

 in small experimental animals. 



If the graft does not take the animal will show all the usual 

 signs of castration. 



In general one is inclined to consider such experiments as 

 sufficient proof for the contention that the influence the testicle 

 has on the sex characters is produced not by intermediation 

 of some kind of nervous reflex beginning in the sexual gland, 

 but by the action of internal secretions. We shall see later on 

 that these experiments taken by themselves are open ta 

 criticism, that is to say, they do not afford sufficient proof 

 for the assumption that the testicle acts really by an internal 

 secretion. 



The medical practitioner must know that successful trans- 

 plantation of testicles is practicable also in man (for literature 

 see especially Mauclaire, 1923). As far as I am aware, the 

 American surgeon Lespinasse was the first to perform a 

 successful testicular transplantation in man. Pieces of testicle 

 were implanted on the musculi recti of a man who lost both 

 testicles in an accident. Sexual capacity was regained and 

 persisted for many months when the patient was under medical 

 observation. 



J 



