Benson A. Cohoe 18 
Ou 
(3). An examination of the secretion phases, observed in fresh sections, 
reveals the fact that under stimulation, the granules of the clear cells 
disappear earlier than those of the dark cells, while in a gland recovering 
from exhaustion, those in the clear cells are the later to reappear. 
(4). In stained preparations of stimulated glands, the granules are 
found to have disappeared from the cells of the dark proximal group, 
and to have reappeared in a gland recovering from exhaustion, in one 
and the same region, around an intercalated duct. The cells of the 
distal clear group, in a section prepared after fixation in any of the 
fluids employed, are never found to contain stainable granules during 
any phase of secretion. 
(5). The cytoplasm of the two kinds of cells exhibits different staining 
properties and affords distinctly different microchemical reactions. The 
proximally disposed granule-holding cell conforms to the classic descrip- 
tion of a serous cell, while the clear distal cell resembles in some degree 
the appearance of a mucous cell. 
The significance of the presence of these two types of cells in this 
gland is as yet doubtful, and must remain so until our knowledge of 
the chemistry of the submaxillary saliva of the rabbit is more exact 
and the microchemical methods at our disposal further developed. The 
role of each cell in the production of the secretion is unknown and, 
indeed, even the presence of a diastatic ferment in this saliva is still a 
debated question. Many suggestive, but by no means convincing, results 
were obtained concerning the nature of these cells through their staining 
and microchemical properties. 
The cytoplasm of the cells afforded many valuable criteria for differ- 
entiating the two types. In the clear cells it is less abundant than in 
the granular cells and contains a basophilic recticulum. It possesses a 
substance which has a marked affinity for hematoxylin and basic stains. 
With acid stains it does not stain so readily as the cytoplasm of the 
granular cell. With P. Mayer’s muchematein, as modified by Bensley, 
03, in sections fixed with Kopsch’s fluid, a typical “ mucous” reaction 
was obtained in these clear cells. With Krause’s so-called mucin stain 
(thionin followed by potassium ferrocyanide) these cells also behaved as 
mucous cells and gave a metachromatic red color. Neither of these 
stains, however, can be regarded as specific for mucin. According to 
Hoyer, go, a metachromatic color with thionin is a positive indication of 
mucin or a mucin-like body. Krause, 95, tested the validity of this 
assertion by successfully staining sections of hyaline cartilage and of 
