CHAP. I.] 



SALIVARY CONCRETIONS TARTAR. 



53 



small, indeed of microscopical dimensions ; sometimes, and then they 

 usually occupy the ducts of the salivary glands, they are much larger, 

 being of the size of a pea andt sometimes very much larger. 



The larger salivary concretions are round or oval, smooth or 

 rough, sometimes of a white, and sometimes of a yellowish grey 

 colour, usually homogeneous, and pulverisable. Sometimes they are 

 hard and stratified, rarely they exhibit a radiated structure and 

 possess a visible nucleus. Rarely, when powdered, they exhibit 

 crystalline fragments. When treated with dilute mineral acids, the 

 mineral salts of the concretion are dissolved, leaving an organic 

 mass. Such concretions usually occur singly in the duct of one of the 

 glands, though more rarely several (as many as ten) are found. They 

 weigh as a rule from 1/5 to 2 grammes, exceptionally as much as 

 3 or 4 grammes, and occur most frequently in Wharton's duct ; 

 in the parotid they occur about ten times less frequently than in 

 the submaxillary gland, and in the sublingual gland they are still 

 rarer 1 .' According to Kiihne, salivary concretions usually contain 

 the salivary diastatic ferment, so that when powdered they act 

 energetically upon starch. 



The following tabular statement 2 exhibits the results of analyses 

 of salivary concretions by various observers : 



Tartar of the Teeth. 



The tartar of the teeth is in great part composed of salts which 

 have been deposited from the saliva, and it therefore has much 

 resemblance to salivary concretions. The tartar occurs usually in 

 masses which are of a yellowish, greenish or brown colour. Besides 

 salts they contain mucus, squamous epithelium cells, and long filaments 

 of Leptothrix buccalis, all of which are rendered evident if a little 

 of the powdered concretion be treated with dilute hydrochloric acid 

 and the residue be examined microscopically. 



1 Hofmann, Lehrbuch der Zoochemie, Wien, 1879, p. 146. 



2 Gorup-Besanez, Lehrbuch der physiologischen Chemie, 4th Ed. (1878), p. 476. 



