HORMONES AND THE MAMMJE 89 



to this point we must consider what influences lead to 

 the original development of the breasts, and give rise to 

 their increased activity during pregnancy. 



As just stated, the breasts form a secondary feminine The 

 characteristic, and in consequence should normally controlling 



be well developed subsequently to puberty in every 



woman. That they are not always so agrees with what istics regulate 



is found in regard to the other sex-characteristics, for, if O f the PE 



there be variety in regard to the degree of total femininity mammae. 



present in different women, it follows that the individual 



characteristics must vary. In this connexion we may 



say, without fear of contradiction, that the woman who 



can and does suckle her children is strongly feminine, 



and that the future of the race is safe so far as she is 



concerned. 



The hormones, then, that lead to the development 

 of the sexual functions and characteristics are responsible 

 for the development of the mammae ; and I have en- 

 deavoured to show that all the hormonopoietic organs, 

 and not the gonads alone, are so concerned. 



Attention must be called to the fact that the casual 

 observer may be misled into the inference that adiposity, 

 which may occur in the region of the breasts as elsewhere, 

 is indicative of true (glandular) mammary development ; 

 but, as a matter of fact, large breasts due to adiposity 

 may be associated with atrophy of the glandular 

 tissue. 



The ovaries and the mammae. In the develop- Relation of 

 ment of maturity in the female ovarian activity plays a mammary 8 

 large part. As is well known, removal of the ovaries development. 

 before puberty leads in all animals (and would almost 

 certainly, therefore, do so in woman) to infantilism of 

 the mammary glands 1 . I have myself observed this 

 on many occasions in young rabbits. Nevertheless, the 

 castrated animal, as will be remembered, grows to a 

 larger size and is fatter than normal. 



In regard to the further development which may 

 1 Marshall, F. H. A., The Physiology of Reproduction, 1910, p. 314. 



