SALIVA IN DISEASE• Salivary Calculi.— As the result, in all pro bability, of some defect in secretion, the saliva occasionally gives rise to the formation of calcu lous matter. Thus, what is commonly called tartar, tends to deposit upon the teeth. Ber zelius has examined this substance, and found that water extracted ptyalin frorn it, and that the remainder was soluble in hydrochloric acid, only a small residue composed of mucus being left unacted upon. Caustic ammonia precipitated phosphate of lime, and ammo niaco-magnesian phosphate from the acid solution.
The peculiar quality possessed by saliva of becoming mucilaginous and adherent, was at tributed by Tiedemann and Gmelin to a solu tion of mucus in alkaline carbonate. This last is present in the saliva of the sheep in such abundance, that when dry it effervesces on the addition of acids. The saliva of the dog, however, contains most, and the saliva of man the smallest quantity of the salt. Ac cording to Tiedemann and Gmelin, the alkaline carbonate of human saliva is a potash salt, while the saliva of the dog and sheep contains carbonate of soda.
The alkaline phosphate contained in saliva exists in larger proportion in that of man, and of the sheep, than in that of the dog. All three contain chloride of sodium in large Salivary calculi only occasionally occur in the human subject, but are frequently ob served in animals. One of these substances from the human subject yielded, according to the analysis of Poggiale, 94, per cent. of phos phate of lime, the remainder being mucus and other animal matters. Wurzer found, in a concretion from the submaxillary gland of a man, carbonate of lime, earthy phosphates, oxide of iron, and manganese.
Calculous concretions, obtained from the salivary ducts of the horse and ass, have been analysed by Lassaigne, Henry, and Caventon, with the following results :— Ranula.—The disease called ranula, which was long supposed to depend upon the deten tion of saliva within the salivary duct, owing to inflammatory closure of its orifice, and the dis tention consequent upon such condition, has been lately shown by Dr. Goruss Besanez# to depend on the development of an encysted tumour within the duct. The fluid evacuated
from ranula has been analysed by him, and its composition determined as follows : — Water - 95'029 Traces of fat and chloride of sodium - - - 1.062 Aqueous extractive matter - 0.923 Albuminate of soda - 2.986 This analysis shows the contained fluid of ranula to differ entirely from saliva, and places it among the products of morbid secreting sacs. Under the microscope, blood corpuscles and inflammatory exudation corpuscles were observed, none of the ordinary characters of saliva appearing. Much curious information has been collected by Dr. Wright with regard to the morbid conditions of saliva, and the production of hydrophobic disease. Among the statements made by various authors are the following. t Hydrophobia.— Ambrose Pare agrees with Galen and Dioscorides in the opinion that morbid saliva may produce hydrophobia by contact with the second skin. The disease is stated by Ccelius Aurelianus to have been com municated to a sempstress who used her teeth to unsew the cloak of a hydrophobic patient. Schenckins states hydrophobia to have been communicated by a sword which had been used some years before for the purpose of destroying a rabid dog. Palinarius relates that a peasant rendered his children rabid by kissing them.
Magendie and Breschet succeeded in pro ducing hydrophobia in a dog by inserting the saliva of a rabid man under the skin of the animal. Dr. Herturch found that out of fifty nine trials, only fourteen animals became affected with real rabies. Mr. Youatt suc ceeded in causing hydrophobia in a healthy dog by inserting as a seton-cord a piece of silk moistened in the mouth of a hydrophobic animal. There appears but little doubt that hydrophobia is really a disease produced by a morbid poison circulating in the system ; nor does the long period which occasionally elapses between inoculation and the develop ment of the disease in any way militate against the correctness or such a view, for we are aware, from the history of other well recognised morbid poisons, how various the period required for development of action is; probably bearing some relation to the tempe rament and general habits of the subject af fected.