14 THE GENITAL GLANDS 



have been made, especially by vendors of expensive 

 patent remedies, to convince the profession that the 

 internal secretion of the testis can be taken as a 

 rejuvenating drug, recalHng the classical story of 

 Medea's cauldron; but, as Biedl says, "exact and 

 carefully controlled experiments with this substance 

 have not been described. ' ' Auto-suggestion probably 

 accounts for much of the alleged benefit. 



CONTROL OF THE GENITAL GLANDS BY 

 INTERNAL SECRETIONS. 



Not only are the genital glands themselves the 

 source of internal secretions, but there is a good 

 deal of accumulating though ill-assorted evidence to 

 show that their own activity is dependent upon 

 chemical messengers (hormones), reaching them by 

 the blood-stream, derived from what we call the 

 ductless glands. 



What is it that makes a man mascuHne, and a 

 woman feminine ? It used to be thought that the 

 testis and the ovary were solely responsible. Now 

 we know that mascuUnity and femininity may 

 persist even after these glands are removed. The 

 mere fact of infertiUty does not aboHsh sex, which is 

 dependent upon the combined working of a num- 

 ber of internal secretions. 



The Ductless Glands before Puberty. — In 

 young animals and in children the development of 

 the ovary, testis, and other parts of the genital 

 apparatus depends upon chemical stimuh received 

 from the pituitary and thyroid glands. Experimental 

 removal of these glands in young animals, or 



