LACTATION 585 



Miss Lane-Claypon and Starling, however, do not contend 

 that the foetus is the sole source of the stimulus for mammary 

 development. On the other hand, they specially mention that 

 the growth of the mammary glands which occurs at puberty, 

 for instance, can only be attributed to ovarian influence, since 

 it does not take place if the ovaries have been previously re- 

 moved. It is not improbable, therefore, that an ovarian stimulus 

 is also responsible for initiating the growth of the glands in 

 Monotremes, while Hill's observations on certain Marsupials 

 afford a clear indication that such is the case in these animals 

 (see p. 576). 



APPENDIX 



Lombroso and Bolaffio ^ have described an experiment in 

 which two female rats were grafted together so that their re- 

 spective circulatory systems were presumably united. Subse- 

 quently to their union they each became pregnant, but at 

 different times. They afterwards produced young, one pre- 

 maturely, and the other at fu^U term. The mammary glands 

 of each underwent the characteristic changes, but they occurred 

 independently and not synchronously. The authors cite this 

 result as evidence against the foetal hormone theory. Moreover, 

 as a result of this and another similar experiment, they conclude 

 that parturition is not induced by a chemical excitant circulating 

 in the blood (see p. 542). 



On the other hand, in the case of the Bohemian pygopagous 

 twins, Rosa-Josepha, the mammary glands of both are de- 

 scribed as haNdng been similarly and simultaneously affected by 

 the pregnancy of Rosa, who bore a healthy boy on April 17, 1910. 

 Milk was afterwards secreted by the breasts of Josepha as well 

 as of Rosa, although Josepha had never conceived.^ 



' Lombroso and Bolaffio, "La Parabiosi e la Questione del Fattori che 

 determinano la Fuz Funzione mammaria e I'lnsorgenza del travaglio di parto," 

 Atti della Soc. Ital. di Obstet. e Gin., vol. xv., 1909. 



" British Med. Jour., Part II., May 28, 1910. The twins are described 

 as being united posteriorly by a common sacrum, but the iliac bones are 

 separate. There is a common anus, perineum, clitoris, and meatus urinarius, 

 but the labia majora are double. The urethra is single for an inch above the 

 meatus, but then it bifurcates. The ureters are normal. The desire to 

 micturate is said to be distinct, but not the desire to defsecate. 



