Variations in the Inorganic Constituents of Mixed and Parotid Gland Saliva Activated by Reflex Stimulation in the Dog

It was previously found (Baxter, 1929-30, 1931) that marked variations occur in the organic matter, ash, and chlorine of the submaxillary and parotid saliva in normal dogs fed with different substances, as well as in the course of the secretion activated by these substances. Subsequently some of the inorganic elements of saliva both from the parotid and from the submaxillary glands of normal dogs were investigated to ascertain whether any connection might exist between the type of stimulus used and the level of any given ion in the saliva. The results of this investigation are presented in this paper. Most of the previous investigators in this field have confined themselves to acute experiments in which the salivary glands were activated by electrical stimulation of the corresponding secretory parasympathetic nerve or by intravenous injection of massive doses of pilocarpine. Werther (1886), who used both methods on dogs and rabbits, was one of the first to examine the inorganic compounds of the submaxillary and parotid saliva. He found in the case of the submaxillary and parotid glands that an increase in the rate of secretion caused a higher concentration of salts in the saliva. The saliva of each of the three salivary glands investigated contained various amounts of salts. Werther’s figures, e.g. for calcium, show that that element was almost twice as abundant in the parotid and sublingual saliva as it usually is in the blood serum. On the other hand, the amount of calcium in the submaxillary saliva was only slightly higher than the average blood serum calcium of the dog. Gregersen and Ingalls (1931) have shown recently that sodium, but not potassium, in the submaxillary saliva of the dog is depend-