ON SOMATIC SEX-CHARACTERS 91 



Influence of Gonads due to Hormones 



The existence and the influence of hormones or 

 internal secretions mav be said to have been first 

 proved in the case of the testes, for Professor A. A. 

 Berthold ^ of Gottingen in 1849 was the first to 

 make the experiment of removing the testicles from 

 cocks and grafting them in another part of the body, 

 and finding that the animals remained male in 

 regard to voice, reproductive instinct, fighting spirit, 

 and growth of comb and wattles. He also drew the 

 conclusion that the results were due to the effect 

 of the testicle upon the blood, and through the blood 

 upon the organism. Little attention was paid to 

 Berthold' s experiment at the time. The credit of 

 having been the first to formulate the doctrine of 

 internal secretion is generally given to Claude 

 Bernard. He discovered the glycogenic function 

 of the liver, and proved that in addition to secreting 

 bile, that organ stores up glycogen from the sugar 

 absorbed in the stomach and intestines, and gives it 

 out again as sugar to the blood. In 1855 he main- 

 tained that every organ of the body by a process of 

 internal secretion gives up products to the blood. 

 He did not, however, discover the action of such 

 products on other parts or functions of the body. 

 Brown-Sequard, in his address before the Medical 

 Faculty of Paris in 1869, was the first to suggest that 

 glands, with or without ducts, supplied special sub- 

 stances to the blood which were useful or necessary 

 to the normal health, and in 1889 at a meeting of the 

 Societe de Biologic he described the experiment he 

 Lad made upon himself by the injection of testicular 



^ * Transplantation dcr Hoden,' Archiv f. Anat. u. Phys., 1849. 



