146 ESSAYS OF A BIOLOGIST 



tive organs must be in some way activated by other 

 ductless glands before they become normal, just as 

 they in their turn must activate the sexual centres 

 in the brain. This phase of the matter is being 

 investigated by many workers to-day; provisionally 

 we may say that pituitary and adrenal cortex are es- 

 pecially concerned. In the second place the gonads, 

 once activated and in normal working order, react 

 upon the other ductless glands. It thus comes about 

 that the relative proportion or relative activity of 

 the parts of the whole ductless gland system is dif- 

 ferent in male and female. Blair Bell is the pro- 

 tagonist of this view. A woman is a woman, he 

 says, not merely because of her ovaries, but because 

 of all her internal secretions, of her endocrine bal- 

 ance as a whole. 



It cannot be said that we have any certainty on 

 the details of this subject. It is clear, however, that 

 some such fundamental difference does exist, and it 

 is therefore further probable that if a woman has a 

 thyroid, say, or an adrenal which for some reason 

 (and there are many possible reasons) is producing 

 an amount of secretion abnormal for a woman but 

 more like that which is produced by a man, she will, 

 in spite of her ovaries, be more masculine in tend- 

 ency. 



I will content myself with one example. The cor- 

 tex of the adrenal gland, if active beyond a certain 

 measure, assists the development of male, prevents 

 the development of female, characters. Women 



