SECRETORY FUNCTIONS IN HUMAN PLACENTA 541 



type cells, whereas in the largest number there is almost no 

 sign of such a function, which fact is worth much attention. 



The large-type decidual cells, as aforesaid, no longer present 

 the ordinary phenomena of secretion for the most part, and yet, 

 at a certian period, dark-stained coarse granular bodies of ir- 

 regular sizes often make their appearance within the bordering 

 membrane of the periphery (figs. 55, 59 to 61) ; various material 

 products having the same staining properties are often de- 

 tected within the interstitium (figs. 70 and 71), which makes 

 one feel that there is a certain formative relation between the 

 two. And, besides, similar products often filling up the blood 

 vessels around them, give the appearance of being absorbed 

 in the vascular organs (fig. 71). Such peculiar products hav- 

 ing been originally observed in the fixed preparations, it follows 

 that they might be an artificial product, a result of the fixatives, 

 and yet from the observations mentioned above it is not diffi- 

 cult to conclude that a certain material which corresponds to them 

 is prepared, perhaps by some special function of the cell mem- 

 brane of the cell concerned, and is sent forth in the direction of 

 the interstitium. And should this supposition prove correct, 

 it would follow that these two kinds of large-type decidual 

 cells are functionally quite independent of one another, though 

 they are genetically of the same origin. 



Looking on the whole of the functions of the decidual cells 

 from the histological point of view given above, I am led to be- 

 lieve that they may be roughly divided into three periods, ac- 

 cording to the course of their development. The first period 

 is seen in all the small-typed decidual cells, the intermediate 

 type so termed by me, and in a portion of the large-typed cells, 

 here the secreting functions are distinctly performed in the 

 same manner as in the stroma cells of villi. In the second 

 period, possibly by the functions of the cell membrane, a certain 

 product is prepared, to be sent forth in the direction of the 

 interstitium. The third period begins after the sixth month of 

 pregnancy, when the cell body in general shrinks considerably, 

 and no plastosomes are to be discovered, besides no particular 

 tissue structures from which inference may be made of the 

 functions performed are to be recognized. And, moreover, cells 



