SALIVA. 



419 



soluble in alcohol contains salivary matter, 

 combined with soda, and its reactions accord 

 perfectly with those of the salivary matter 

 found by Gmelin in human saliva. Phosphate 

 of potash, phosphate of soda, and a small 

 proportion of carbonate of lime, also exist in 

 this saliva. 



The saliva of the sheep, according to Ber- 

 zelius, is clear, and not adhesive, like that of 

 the dog. It has a feeble saline taste, and a 

 faint alkaline reaction. When dried, it leaves 

 1'68 per cent, of solid matter, which forms an 

 opaque white membrane, and becomes moist 

 by exposure. Chloride of sodium is extracted 

 from this mass, in octahedral crystals, by di- 

 gestion with alcohol. The salts of iron yield 

 ample evidence of the presence of sulpho- 

 cyanogen in the alcoholic solution. The por- 

 tion of solid matter insoluble in alcohol, when 

 treated with water, yields little else than salts. 

 So completely is this the case, that the eva- 

 porated aqueous solution scarcely gives out 

 an empyreumatic odour while being heated to 

 redness. The mass, which is insoluble both 

 in water and alcohol, is brittle and mem- 

 branous, insoluble in acetic acid, and not 

 gelatinised when moistened by it. The acid, 

 however, dissolves out phosphate of lime, after 

 which it is precipitable by the addition either 

 of ammonia or oxalate of lime, but not by in- 

 fusion of galls. 



The following is an analysis of the saliva of 

 the sheep : 



Water 98'90 



Matters soluble in alcohol (ex- 

 tract of meat, a matter which 

 crystallises chloride of sodium 

 in octahedra, chloride of so- 

 dium, and a small proportion of 

 sulphocyanide of sodium) . (HI 

 Matters soluble in water only 

 (traces of ptyalin, a consider- 

 able quantity of phosphate of 

 soda and chloride of potassium, 

 and carbonate of soda) - - 0*82 

 Matters insoluble in water and 

 alcohol (mucus or coagulated 

 albumen, and a small quantity 

 of phosphate and carbonate of 

 lime) ----- 0'05 



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 



quantity. The sulphocyanide which exists in 

 the saliva of man and of the sheep cannot be 

 satisfactorily detected in the dog. Ptyalin is 

 almost wanting in the saliva of the 'sheep, 

 while that of the dog is deficient in animal 

 extractive matter. 



Lassaigne and Leuret found the same quan- 

 tity, viz. about one per cent, of solid matters, 

 in the saliva of man, the horse, and the dog. 



The saliva of insects has been collected by 

 Reuzzer*, but not in quantity to admit of 

 analysis. It was found, however, to yield an 

 alkaline reaction. 



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 from 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. 



Analysis yielded the following result : 



Ptyalin - - - - - I'O 

 Salivary mucus - - - - 12'5 

 Earthy phosphates - - - 79-0 

 Animal matter soluble in hydro- 

 chloric acid - - - - 7'5 



100-0 



Vauquelin and Langier found one of these 

 masses to contain 



Water 0'07 



Salivary mucus insoluble in acids 



and in water - - - - 0'13 

 Phosphate of lime, with traces of 



magnesia - 0'66 



Carbonate of lime - 0*09 



Animal matter soluble in hydro- 

 chloric acid - 0'05 



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 : 



* Physiol. Untersuch. iiber die thierische ITaus- 

 haltung der Insecten. Tub. 1817. 



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