486 GENCHO FUJIMUEA 



INTRODUCTION 



In recent times, along with an increase of knowledge on 

 internal secretion, it has been imagined by many authors that 

 in the placenta and the decidua there should exist such a func- 

 tion. According to the literature which I know, Lettule and 

 Larrier ('01) are those whose attention was first drawn to this 

 subject. They detected in the syncytium layer a kind of gran- 

 ular body termed Tlasmoidale Kugeln.' This body they took 

 to be a secretion of the placenta. Subsequently, Veit ('02) 

 attempted to trace the cause of eclampsia, and Behm ('03) 

 the cause of morning-sickness to the function of the syncytium, 

 and Bouchacourt ('03) observed an increase of lactation by using 

 some placental preparations. Further, Halban, supported by 

 his plentiful clinical observations, stated that the swelling of 

 the nipples noticeable in a newborn child, the congestion and 

 hyperplasy of the uterus, the hypertrophy of the mammary 

 glands of a pregnant mother, and hypertrichosis are all probably 

 due to his so-called 'Reizstoff,' which is thought to be a product 

 of the placenta. Among other things, it seemed he tried to 

 deduce the existence of the closest functionary correction be- 

 tween the placenta and the mammary glands. Since the result 

 of Halban's studies was published, the functions of internal 

 secretions likely to exist in the placenta drew general attention, 

 and thereafter studies of this subject followed quickly one 

 after the other. In the present essay I have refrained from 

 chronologically relating all the results of these researches, 

 but instead, with a view to giving only a general idea of what 

 is known about this subject at present, I have confined myself 

 to the summing up of all the points of the investigations made 

 by the various authors up to now, and to dividing them into a 

 few large sections along the lines of experimentation, biolog- 

 ical chemistry, and histology. 



Now, in the early experimental investigations, it was the 

 first attempt of the various authors to investigate chiefly the 

 effect which the placenta has upon the mammary glands, and 

 the methods employed were either to inject into the animal 

 used as the subject of the experiment an extract of the placenta 



