180 Finer Structure of the Glandula Submavxillaris 
Tue STAGES OF PHYSIOLOGICAL ACTIVITY. 
The microscopic appearances of the hardened and stained sections of 
the gland, taken at any stage of activity, simulated closely the conditions 
found in the preparation of the fresh gland of the corresponding stage, 
with this notable exception, that while in fresh sections of the gland, 
granules were found present in both varieties of cells, in the fixed 
sections they occurred only in the group of cells lying next to an inter- 
calated duct. No reagent so far employed has had the property of fixing, 
to any extent, the granules in the clear distal group of cells. Always 
associated with this lack of granule fixation, there was present more or 
less shrinkage of the cell cytoplasm. It was, moreover, to be observed, 
that the newly formed granules, in a gland recovering from exhaustion, 
were more readily soluble than the granules of a resting gland, for which 
reason, while in the fresh tissue abundant granules might be present, 
the corresponding fixed specimen might display scanty granulation. 
After a period of three hours’ stimulation with pilocarpine a thin, 
fresh section of the gland, examined in aqueous humor, showed all of 
the cells still loaded with granules. In the cells of the dark areas, 
close to the ductules, the granules varied much in size and occurred in 
irregular masses. The cells of the clear areas were still filled with 
granules. The nuclei were discernible with difficulty. In a fixed prepa- 
ration of the gland, stained with Heidenhain’s iron hematoxylin and 
eosin, the cells were seen to be in a condition of partial exhaustion. 
There were fewer granules present in the cells of the dark areas and the 
cytoplasm of these cells was clearly differentiated from the more lightly 
stained cytoplasm of the cells of the clear areas. With eosin the cyto- 
plasm of the granular cells was stained a lively red, while that of the 
_distal, clear cells was feebly colored by this stain. The nuclei of the 
granular cells were now more readily visible than in the resting gland, 
and showed a tendency to assume a position more central in the cell. 
Secretion canaliculi could now be seen in both kinds of cells, but were 
observed to be more numerous in the clear cells. In the granule-holding 
cell they were found to be short and broad without any apparent branch- 
ing. 
At the end of four hours in fresh sections, the blood vessels of the 
gland were seen to be much congested, and both cell complexes showed 
fewer granules. It was to be noted that the granules in the cells of 
the dark areas appeared to persist longer under stimulation than those 
in the cells of the clear areas. After seven hours the gland was found 
shrunken, with the blood vessels engorged. The two cell complexes could 
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