THE PLACENTA AS AN ENDOCRIN OEGAN 655 



tion of menstruation in virgins there may occur a secretion of milk. 

 This phenomenon was also reported by Avicenna and Schacher. It is an 

 interesting commentary upon the times that the occurrence of such a hap- 

 pening served to cast doubt upon the virginity of the individual reacting 

 thus peculiarly. Aristotle assigned to milk a source analogous to the 

 menstrual flow. The observations of Puech and Gauthier on vicarious 

 mammary menstruation, and of Schlicter on the relationship of menstrua- 

 tion and lactation, all served to draw into intimate contact the functions 

 of milk secretion and gonad activities. 



The Placenta as a Factor in Milk Secretion. As an Initial Stimulant 

 to Secretion. Obviously the most general striking evidence of a causative 

 relationship is presented by the initiation of milk secretion in the mother 

 after the birth of the infant. Here again attempts were made by Goltz, 

 Mironow, Ribbert, Pfister, and others, to trace the source of stimulus to 

 nerve impulses but without success. Clinical evidence, presented by Hal- 

 ban, eliminated the uterus as a causative factor, while Hildebrandt and 

 others demonstrated that the act of sucking is inadequate for continued 

 secretory functioning. The possibility that the change in circulatory 

 arrangements following parturition might be a factor was summarily 

 disposed of by Halban, for whom the act of birth alone was insufficient. 

 Bouchacourt tentatively placed the increased milk secretion as a result 

 of a ferment formation by the placenta, while Letulle and Nattan-Larrier, 

 on a basis of histological studies, attributed the stimulation to the pres- 

 ence of a secretion demonstrable as droplets in the placental syncytium. 

 Ercolani, Creighton, Letulle, and Pinoy considered that degenerative 

 changes in the placenta released substances causing the assumption of 

 the function of milk secretion by the mammary gland. Hildebrandt, 

 correlating these various hypotheses, broached the idea that the entire 

 uterine contents were concerned in the regulation of milk secretion, 

 and that during pregnancy there is given off from the growing ovum 

 an influence on the milk-producing glands in the sense of a stimulus 

 to growth (but inhibitory to milk secretion). On the birth of the 

 fetus, this inhibitory influence is removed, and the secretory function 

 of the glands is taken up with increasing facility. The principle of this 

 hypothesis was accepted by Niklas, but he tended to limit the source to 

 the placenta, since "by the action of Ei-material l (placenta and fetus) it 

 is just as possible to obtain a passing milk secretion and accompanying 

 mammary gland hyperplasia with virgin, as with pregnant animals." 

 Physiologically there is apparently, at birth, a flooding of the maternal 

 blood with the stimulant that, after a certain period of incubation, initiates 

 the activity of the mammary glands. Although Keiffer (a-) (&) claimed 

 that the placenta produces a substance regulating milk secretion and Asch- 

 ner and Grigoriu, Lederer and Pribram, Basch, and others, obtained a 



1 Products* of the fertilized egg. 



