SECRETORY FUNCTIONS IN HUMAN PLACENTA 545 



and decidua, each contained plastosomes as a constant in- 

 gredient of its protoplasm, and that a majority have at the same 

 time a certain quantity of either hpoid granules or vacuoles, 

 or of both, and, consequently the minutes histological structure 

 of these cell groups bears a close resemblance to that of 

 both the internally and externally secreting cells. And, more- 

 over, these main components of protoplasm or cell body are, 

 according to their functions, as closely correlated to one another 

 as they are in the glandular cells. Now, taking a general sur- 

 vey of this correlation, it was found in my study that the plas- 

 tosomes, being the first constituent, appear for the most to be 

 the matrix of lipoid granules from which the latter rise, and as 

 ia proof of this argument, I will cite the stroma cells of villi, 

 in which the correlation between the two is very closely shown. 

 We can notice it somewhat in the Langhans' and decidual cells, 

 and if we closely examine the manner in which the lipoids appear 

 in these cells, it will be found that they always rise from gran- 

 ular bodies which are very small and strongly siderophil. I 

 believe that these may be rightly compared with the so-called 

 ' Primargranuhs ' which Heidenhain found in the common 

 glandular cells, and even though they appear very small, they 

 do appear as a perceptible body. There is no evidence to be 

 found of their appearing as slowly growing and increasing, as 

 Heidenhain assumes to be the case, from an infinitely small 

 body which is hardly seen microscopically until they enter the 

 vision of a microscope. Rather is it found that some of them 

 bear a close resemblance to the granular plastosomes in their 

 size and staining properties, clearly indicative of images running 

 over between the two (figs. 28, 29, 31, 36, and 42), which will 

 account for my argument that plastosomes should be deemed 

 the matrix of the lipoid formation. And, for the second rea- 

 son, I will give the fact that the plastosomes, either being con- 

 siderably reduced in their quantity or having gone out of exist- 

 ence, as the lipoid formation progresses, are scarcely detected. 

 Such is the fact which is often noticed in all the cell groups 

 other than the stroma cells of villi, and a part or the whole of 

 the plastosomes cannot but be seen as having been consumed 



