466 



INTERNAL SECRETIONS 



of the asexual embryonic soma in a double sense : they may 

 either stimulate or inhibit growth. Herbsi (1901) was the first 

 to point out many years ago that there may be inhibition of 

 somatic development by sex hormones, and the experiments of 

 Steinach, and especially those of Goodale, Pezard and Zawa- 

 dowsky on fowls, have shown that such an inhibitory influence 

 on the part of the sex hormones actually occurs. 



In the following scheme the experimiental results relating to 

 the dependence of the sex characters upon sex hormones as 

 recorded in Chapters II., III. and VI. are summarised. 



THE BEARING OF THE SEX HORMONES ON THE SEX CHARACTERS. 



+ promotion of development or furtherance ; — inhibition ; 

 it promotion or furtherance and inhibition of different parts of 

 an organ ; o no influence. 



In reality the relation between sex characters and sex 

 hormones is a much more complicated one than can be expressed 

 by the terms "furtherance" or "inhibition." But as we have 

 not yet sufficient knowledge of the whole complex of relations, 

 it is necessary to restrict ourselves somewhat so as to simplify 



