t 1005. If allowed to stand, a whitish
precipitate is formed. Examinations with the microscope show it to be
composed of minute, granular cells and oil globules, mingled with
numerous scales of epithelium. According to Bidder and Schmidt, the
composition of saliva is as follows:

Water, 995.16
Organic matter, 1.34
Sulpho-cyanide of Potassium, 0.06
Phosphates of Sodium, Calcium and Magnesium, .98
Chlorides of Sodium and Potassium, .84
Mixture of Epithelium, 1.62
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1000.00

Two kinds of organic matter are present in the saliva; one, termed
_ptyalin_, imparts to the saliva its viscidity, and it obtained from the
secretions of the parotid, submaxillary and sublingual glands; another,
which is not glutinous, is distinguished by the property of coagulating
when subjected to heat. The saliva is composed of four elementary
secretions, derived respectively, from the mucous follicles of the
mouth, and the parotid, the submaxillary, and the sublingual glands. The
process of its secretion is constant, but is greatly augmented by the
contact of food with the lining membrane. The saliva serves to moisten
the triturated food, facilitate its passage, and has the property of
converting starch into sugar; but the latter quality is counteracted by
the action of the gastric juice of the stomach.

GASTRIC JUICE. The minute tubes, or follicles, situated in the mucous
membrane of the stomach, secrete a colorless, acid liquid, termed the
gastric juice. This fluid appears to consist of little more than water,
containing a few saline matters in solution, and a small quantity of
free hydrochloric acid, which gives it an acid reaction. In addition to
these, however, it contains a small quantity of a peculiar organic
substance, termed _pepsin_, which in chemical composition, is very
similar to ptyalin, although it is very different in its effects. When
food is introduced into the stomach, the peristaltic contractions of
that organ roll it about, and mingle it with the gastric juice, which
disintegrates the connective tissue, and converts the albuminous
portions into the substance called chyme, which is about the consistency
of pea-soup, and which is readily absorbed through the animal memb