SECRETORY FUNCTIONS IN HUIVIAN PLACENTA 547 



product of lipoids, and the contents should possibly be secretions 

 as transparent as water. 



According to the arguments given above, the various cell- 

 groups of the placenta and decidua entirely agree with the ob- 

 servations of the glandular cells not only in their structure, but 

 also in the histological changes that follow their functions, and, 

 therefore, there is no room for doubt that secretion should 

 be existent in them also. And it will be briefly stated, con- 

 cerning their secreting phenomena, that probably hpoid gran- 

 ules rise directly from plastosomes, and then, the former, grow- 

 ing in size, slowly change to the vacuoles, viz., secretions, 

 and are thus thrown out of the cell body at times. If looked 

 at from the standpoint of their secretion formation these cells, 

 for the most part, closely resemble the external secretory cells, 

 but viewed with regard to their inner structure in which they 

 keep secretions within their own bodies for a comparatively long 

 period and thus for the most part present a more or less conspic- 

 uous foamy image, they should be rather compared with the 

 various internal secretory cells, which are observed in the ovary 

 and the cortex of suprarenals. The principles of the phenomena 

 of secretion, as aforesaid, look very simple indeed, and yet these 

 phenomena do not make their appearance in one and the same 

 cell necessarily at the same time. On the contrary, it is cus- 

 tomary that within different parts of the same cell body the 

 various stages of phenomena appear, one after the other, in conse- 

 quence of which the structure of each individual cell becomes 

 comparatively complex and diverse. Each individual cell, while 

 repeatedly performing its secreting functions in this manner, 

 gradually increase in its size, and it is customary for the cell to 

 grow considerably as it reaches the height of secretion. Even 

 the syncytium layer whose cell border is indistinct, is generally 

 very thick at the height of secretion, and the gradual increase 

 in the size of the cell along with the rise of its secreting functions 

 in this manner may be partly due to the accumulated assemblage 

 of the secretions, though at the same time it cannot be denied 

 that the rise of secreting functions is attended by the increase 

 of the protoplasm and the growth of the nucleus. 



