94 THE SEX-COMPLEX 



states that the administration of thyroid extract to 

 lactating animals increases the flow. 



Effects of The suprarenals and the mammae. So far as I 



injections of , . . . 



suprarenin. know no observations have been recorded on this 

 point except those made by Ott and Scott 1 . These 

 observers found that suprarenin inhibits the secretion 

 of milk. 



Effects of The thymus and the mammae. Ott and Scott 1 



the thymus. s ^ a te that injections of thymus extract excite the 

 secretion of milk. 



It will be obvious from the foregoing remarks how 

 little is known of the influence of the ordinary internal 

 secretions on mammary secretion. It appears that the 

 most feasible method of reaching a conclusion, apart 

 from direct experimentation which would be extremely 

 complicated, is the application to the question of the 

 metabolism of milk-secretion of the principles of the 

 maternal- foetal metabolism, and its relation to the in- 

 ternal secretions. 



The question The foetal hormone. Since the work of Lane- 

 1 Claypon and Starling 2 attention has been riveted on 



affecting the the hormonic theory of mammary activity and milk- 



naammee. 



secretion ; and at the present time it is unnecessary 

 to discuss the nervous theory, or the way in which it 

 has been refuted by transplantations of mammary 

 gland tissue 3 , and by observations made on paraplegic 

 patients who have become pregnant and have nursed 

 their children subsequently 4 . It is now accepted that 

 the whole cycle of breast activity is biochemical. 



Lane-Claypon and Starling performed a number of 

 experiments which proved, they thought, that the growth 

 of the mammary glands during pregnancy is due to 



1 Ott, I., and J. C. Scott, Therap. Gaz., 1912, vol. xxxvi, p. 761. 



2 Lane-Claypon, Janet E., and E. H. Starling, Proc. Roy. Soc., 

 Ser. B, 1906, vol. Ixxvii, p. 505. 



3 Ribbert, A., Archiv. /. Entwick.-MechaniL, 1898, vol. vii, p. 4. 



4 Routh, A., Trans. Obstet. Soc., 1897, vol. xxxix, p. 191. 



