[Rt.print?d from the PROCEEDINGS OF THE ROYAL SOCIETY, B. Vol. 77] 



An Experimental Enquiry into the Factors which Determine the 



(-rroti'th and Activity of the Mammary Glands.* 

 By Miss J. E. LAXE-CLAYPON, D.Sc. (Lond.), and Prof. E. H. STARLING, F.R.S. 



(Received February 12, Read March 1, 1906.) 

 (From the Physiology Laboratory, University College, London.) 



[PLATE 19.] 



The correlation between the mammary glands and the other organs 

 concerned in generation presents perhaps the most striking example of the 

 interdependence of the growth and activities of different organs of the body. 

 Although the manner in which this correlation is brought about has been the 

 subject of speculation for many years, especially among medical men, it 

 is only quite recently that any attempt has been made to apply experimental 

 methods to its explanation. 



In the case of the mammary glands we have organs which are present in 

 both sexes, and at birth are in the same immature condition. In both sexes 

 there is frequently, during the few days after birth, an enlargement of the 

 glands and an actual secretion of fluid, which is known as " witch's milk." 

 This state of activity disappears at the end of the first or second week, and 

 till puberty the glands remain in the same undeveloped condition. At this 

 period in Man the first difference appears between the mammary glands of 

 the two sexes> a rapid growth taking place in the female, and accompanying 

 the commencement of the ovarian functions. 



During adult life there is apparently at each osstral period a slight and 



* lu this investigation the operations and inoculations were carried out by 

 E. H. Starling, and the preparation of the extracts and the microscopic examination of 

 the glands by J. Lane-Claypon, 



