SECEETOEY FUNCTIONS IN HUMAN PLACENTA 557 



glands) and the important internal secretory cells (luteal and 

 interstitial cells of ovary, the cortical cells of suprarenals), and 

 there exists no radically great difference between the two. 

 That is to say, suppose we now take lipoid granules for secre- 

 tory granules and vacuoles for secretions, and naturally these 

 cell groups in placenta and decidua should come under the same 

 category as glandular cells, and there would be no doubt what- 

 ever that the former have certain secreting functions in 

 themselves. 



2. The secreting phenomena of placental and decidual cells, 

 with only the exception of the large-type decidual cells, gener- 

 ally present themselves as in the case of the ordinary glandular 

 cells, with the changes which commonly appear in the structure 

 of the cell bodies and almost under the same form. Now, 

 looked at from the histological viewpoint, the secretions prob- 

 ably rise from the ' plastochondrin, ' and then first passing 

 through the period of minor granules which corresponds to 

 Heidenhain's ' Primargranulis, ' they gradually grow in size 

 and form into the ordinary lipoid granules, which latter, 

 being liquefied continuously, change directly to the secretions 

 (vacuoles). And, in this matter, it seems that the series of 

 histological changes ordinarily even in the same cell body take 

 place at different times and in different regions, so that the 

 changes make their appearance in repetition secondarily, thirdly, 

 and so on, which fact is responsible for the intricacy of struc- 

 ture which sometimes occurs in certain cells. 



3. The methods of discharging secretions, if in the syncy- 

 tium layer, are that the vacuoles finally rupturing themselves 

 in several parts of the superficial layer cause their contents — se- 

 cretions — to escape directly into the intervillous spaces in a 

 striking manner, though in the other cell groups the secretions 

 for the most part cannot but be recognized as passing out 

 by 'osmose.' And, of all the secretions, it should be noted 

 that those which come from the syncytium layer, decidual 

 cells, uterine glandular cells (a part) and also probably from the 

 Langhans' islets are absorbed by the mother's body, while 

 those which pass from the ordinary Langhans' cells and the 

 stroma cells of villi are absorbed in the fetal side. 



