MAMMARY GLANDS IN ENDOCRIN RELATIONSHIPS 643 



(1900, 1904) added to this, observation the fact that the castration of 

 young animals prevented the onset of the jmbertal mammary develop- 

 ment, but that when the ovaries that had been removed were successfully 

 implanted in some other portion of the organism, normal mammary 

 growth resulted. These investigations having been confirmed by Al- 

 terthum, and supported by the work of Foges (a.) (&) (c) (d) (1901-1908), 

 and Hegar, were approved on theoretical grounds by Fellner, and no 

 doubt, at present, exists that the ovaries play a major part in the growth 

 of the mammary glands at puberty. 



Menstrual Growth Impulse. Knauer having demonstrated that 

 ovarian castration inhibits the onset and duration of menstruation, Halban 

 (1905) extended the observation to the mammary changes during men- 

 struation, and came to the conclusion that the stimulus for the third 

 growth impulse likewise arises from an ovarian secretion, in which opinion 

 Lane-Claypon and Starling concur. 



Pregnancy Growth Impulse. The source of the stimulus for the 

 mammary hyperplasia of pregnancy has occasioned much controversy. 

 Although Basch favored the idea that the ovary constitutes the main factor 

 involved in this, as in the other periods of growth, Halban (1905) having 

 noted clinically that normal mammary growth occurs during pregnancy, 

 even after bilateral ovariectomy, strongly opposed the hypothesis. The 

 investigations of Biedl, Mainzer, Cramer and Lane-Claypon and Starling 

 support Halban's contention, while the experiments of Lane-Claypon and 

 Starling indicate quite another source for the stimulus. Such evidence 

 justifies the belief that the ovary takes a minor part, if any, in the 

 mammary growth of pregnancy. 



Milk Secretion and the Ovary. The report of Lajoux, that an in- 

 creased milk secretion was obtained from cows after castration, together 

 with the observations of Halban and others that the mammary glands go 

 on to full secretory activity after the ovaries have been removed during 

 pregnancy, fail to support the conclusions of Temesvary and Bacher, who 

 claim to have obtained an increased secretion of milk after the injection 

 of ovarian extracts. Moreover, Fellner (&), Lane-Claypon and Starling, 

 and MacKenzie were unable to confirm these results, although MacKenzie, 

 using ovarian tissue, minus corpus luteum, did obtain some galactagogue 

 activity. 



These facts and further decisive experiments, later to be described, 

 show that the ovary is not the galactagogic agent par excellence. 



The Corpus Luteum and Mammary Activity 



To Prenant can be given the credit for first having called attention 

 to the probability that the corpus luteum is a ductless gland. Interest 



