INTERNAL SECRETIONS OF SEXUAL GLANDS 8i 



It is of great interest to ascertain whether in those organs, 

 which have an endocrine function besides their other special 

 function, such as the pancreas and the sexual glands, the 

 internal secretion is really produced by the same cellular 

 elements as the external secretion. This question will be 

 discussed in the case of the sexual gland in Chapters IV. and V. 



A. TRANSPLANTATION.! 



The first experiment upon the transplantation of the sexual 

 glands was performed by John Hunter in 1762 on fowl. Berthold 

 (1849) i^ade a similar experiment on cocks two or three 

 months old. He removed the testicles of several birds; in one 

 of them he replaced the testicles into the abdomen (auto- 

 transplantation); in the abdomen of a second castrated bird 

 the testicles of another cock were placed (homoiotransplanta- 

 tion). The engrafted testicles " took " in different places, normal 

 or abnormal, especially on the intestine. The appearance of 

 the birds was like that of normal cocks. Two months later 

 Berthold removed the engrafted testicles in one of these; the 

 bird became a capon. Some other experiments of a similar 

 kind were also performed by Berthold on cocks. He found 

 the engrafted testicle five months after the transplantation 

 adhering to the large intestine and containing spermatozoa. 

 Berthold concluded from his experiments that the character- 

 istic features of sexual maturity are caused by the testicle 

 producing some kind of substance, and through this changing 

 the composition of the blood which reacts on the organism in 

 general, especially on the nervous system. We thus see that 

 the fundamental principles underlying our knowledge of the 

 internal secretions of the sexual glands had been already laid 

 down by Berthold seventy-five years ago. But in those days 

 nobody seems to have taken any interest in this matter and 

 Berthold's experiments were forgotten; they remained too 

 isolated to have any immediate bearing on physiology and 



^ Manifold terms are in common use to describe the different forms 

 of transplantation. We shall confine ourselves to the following: 



yi w/otransplantation — or transplantation in the body of the same 

 individual. 



Howoiotransplantation — or transplantation into the body of another 

 individual of the same species. 



i/e/erotransplantation — or transplantation into the body of an animal of 

 another species. 



