SECRETION AND COMPOSITION OF PAROTID SALIVA IN BUFFALOES      267

The animal with salivary fistula of the parotid duct was fed on green grass.
The quantity of saliva collected during mastication was 42 mls., but when animal
was fed on dry bhoosa there was a copious flow of saliva measuring 102 mls. The
character of the food appears to play an important rôle on the parotid secretion,
and dry food excites production of a larger quantity of saliva.

                                          ACTION OF DRUGS

Two grains of pilocarpine nitrate and a grain and a half of arecoline hydro-
bromide were injected at an interval of 24 hours between each. They produced
a copious flow of saliva five minutes after injection. Atropine is an antagonistic
to pilocarpine, and when injected in one-grain dose it markedly reduced the secre-
tion. The action of the drugs on the parotid secretion is shown in the following
table :—

                                                   TABLE I

Pilocarpine stimulates the parasympathetic nerve endings and thus an exces-
sive secretion is produced. Atropine on the other hand paralyses the termina-
tions of the secretory fibres of the chorda tympani and reduces or inhibits secretion.
This is not due to any action on the salivary cells, but to the failure of nerve
impulses. Pilocarpine injected after a large dose of atropine failed to produce
excessive secretion.

                  PHYSICAL CHARACTER AND COMPOSITION

The saliva was clear, colourless, watery and translucent, having a specific
gravity of 1008. The reaction was alkaline and the pH . was 8.8, which was
determined by the use of the colorimetric method.

The saliva contained no mucin, but a small quantity of protein was present.