90 



THE SEX-COMPLEX 



Relation of 



mammary 8 10 

 deveiopment. 



Effect of 



secretion in 



The relation 



mammary 



activity. 



take place in the mammae a distinction must be made 

 between that which occurs during gestation and im- 

 mediately preceding lactation, and that actually con- 

 cerned in the secretion of milk. 



It is certain that once the mammary glands have 

 become fully developed the ovary exerts little direct 

 influence over their further activity ; indeed, some assert 1 

 that during the reproductive period the ovarian secretion 

 inhibits mammary activity. I believe, however, that 

 it is not so much a question of ' inhibition ' as that the 

 ovary causes the excretion of lime salts, a process in 

 which the mammary glands are also concerned. Atten- 

 tion has already been drawn to the fact that normally 

 the two processes ovary-induced and mammary 

 excretions may not be compatible, since they are con- 

 cerned with more or less identical processes ; and this 

 fact is well demonstrated by the absence of menstruation 

 during the first months of lactation in normal circum- 

 stances, although subsequently, when a metabolic re- 

 adjustment has taken place, menstruation may be, and 

 normally is, re-established during the later months of 

 lactation often to the detriment of the mother (p. 202). 



Further, it has been shown quite definitely by veter- 

 surgeons2 that in cows in which lactation has 

 been present for many years oophorectomy increases the 

 quantity and richness of the milk. It is obvious, of course, 

 that the effect of oophorectomy in this respect can only 

 be observed in those animals which have borne young. 



It has been suggested by Bouin and Ancel 3 , 

 O'Donoghue 4 and others that the corpus luteum 

 furnishes an internal secretion which stimulates mam- 

 mary growth during pregnancy. The evidence, however, 

 on this point appears to be against such an inference, 

 for the corpus luteum is most prominent early in preg- 



1 Battuaud, J., Rev. de Mai. de la Nutrit., 1909, vol. vii, p. 260. 



2 Hobday, F. T. G., Castration and Ovariotomy, 1914, 2nd ed. 



3 Bouin, P., and P. Ancel, Compt. Rend. Soc. Biol, 1912, vol. Ixxii, 

 p. 129. 



* O'Donoghue, C. H., Quart. Journ. Micr. Soc., 1911, vol, Ivii, p, 187. 



