SECRETORY FUNCTIONS IN HUMAN PLACENTA 517 



condition, of the pancreas of the rabbit, the oesophagus glands 

 of the frog, and the gastric glands of the water lizard, by Langley 

 ('79 and '89), whose exposition of the correlation is best authen- 

 ticated, it will be noted that during suspense of their func- 

 tions glandular cells are generally glutted with secretory granules, 

 whereas as secretion begins the granules gradually decrease and 

 disappear, in consequence of which in each cell will appear a 

 sharp demarcation between the homogeneous wide outer layer 

 and the remaining granular inner layer. This observation of 

 Langley has been repeatedly proved by many other authors in 

 many other glands, and its validity except in a small number of 

 cases, has been recognized by nearly everybody. 



For convenience, I defer to a later section a minute explanation 

 of the functional significance of the thread-like production which 

 is found in the basal part of glandular cells. 



Even in mucous cells it has been universally acknowledged 

 by many authors since F. E. Schultze ('64) that there are gran- 

 ular bodies in large numbers at a fixed period of secretion, and 

 at the time when secretion is very high these granules gradually 

 disappear as in the serous cells (Langley, '79 ; Biedermann, '82) . It 

 seems therefore that in the forms of secretion formation mucous 

 cells agree, for the most part with the serous cells. However, the 

 reason why both differ widely in their structure is that in the 

 latter the secretion is, for the most part, speedily drained into the 

 glandular lumen at the time of secretory function, whereas 

 in the mucous cells it is formed within the cell bodies, besides 

 being stored up there for a certain period, thus giving the cells 

 a peculiar structure and a characteristic clearness. 



In short, in the aforementioned two kinds of glandular cells, 

 the large quantity of secretory granules always to be seen in 

 both during suspense of secreting functions disappears by degrees 

 as the functioning begins. In view of this fact, we have no 

 doubt whatever that, at the time of secretion, the granules 

 always play an indispensable part as the mother-ground for 

 the secretions and, since secretory granules are generally deemed 

 a solid production, according to the investigations of many authors 



JOURNAL OF MORPHOLOGY, VOL. 35, NO. 3 



