DIGESTION OF FOOD. 827 
Some of these we now proceed to state briefly. To begin 
with the pancreas, it has been shown that, when the gland is 
not secreting—i.e., not discharging its prepared fluid—or dur- 
ing the so-called resting stage, the appearances are strikingly 
different from what they are during activity. The cell pre- 
sents during rest an inner granular zone and an outer clearer 
zone, which stains more readily, and is relatively small in size. 
The lumen of the alveolus is almost obliterated, and the in- 
dividual cells very indistinct. After a period of secreting 
activity, the lumen is easily perceived, the granules have dis- 
appeared in great part, the cells as a whole are smaller, and 
have a clear appearance throughout. Coincident with the 
changes in the gland’s cells it is to be noticed that more blood 
passes through it, owing to dilatation of the arterioles. 
Fie. 278.—Section of mucous gland (after Lavdowsky). In A, gland at rest; in B, after 
secreting for some time. 
Again, the course of the changes in the salivary glands, 
whether of the mucous or serous variety, is very similar. In 
the mucous gland in the resting stage the cells are large, and 
hold much clear matter in the interspaces of the cell network; 
and, as this does not stain readily, it can not be ordinary 
protoplasm. This, when the gland is stimulated through its 
nerves, disappears, leaving the containing cells smaller. It 
has become mucin, and may itself be called mucinogen. 
It is to be noted that, as the cells become more protoplasmic, 
less burdened with the products of their activity, the nucleus 
becomes more prominent, suggestive of its having a probable 
directive influence over these manufacturing processes. 
Substantially the same chain of events has been established 
for the serous salivary glands and the stomach, so that we 
may safely generalize upon these well-established facts. 
