242 DISEASES OF THE TEETH, ETC. 



jaws by gritting against the teetli : these constituting the 

 evils arising from its presence. In general, the growth of 

 this kind of calculus is extremely slow ; so that it is some 

 considerable time before such effects are produced. When 

 it has attained sufficient magnitude to cause obstruction, the 

 portion of duct between it and the gland becomes swollen 

 from the accumulation of saliva. According to the analysis 

 of Thenard, these calculi are composed of calcareous phosphate 

 in combination with some little carbonate of lime. 



Treatment. — We possess no means of dissolving these 

 calculi; but we can extract them, and in some cases with- 

 out cutting into the duct, which is an operation now 

 and then succeeded by a troublesome fistula. When the 

 stone proves to be at the buccal orifice of the canal, and 

 the molar teeth present the only obstacle to its escape, it 

 will often be sufficient to extend the cheek and give it a 

 good shake or two with the hand to dislodge it. Should 

 the calculus appear to be strangulated within the canal, we 

 must divide the stricture first. This may be done by fixing 

 the mouth wide open with' a ball-iron, and introducing a 

 bistoury tied to a stick, to serve as a long handle, while the 

 other hand is engaged in drawing the tongue out of the 

 way. Should the stone not fall out after the division of the 

 stricture, it may be seized with forceps and extracted. A 

 mash or liquid diet ought to follow the operation. 



Even when not at the orifice, but felt externally some 

 way within the canal under the skin, should the calculus not 

 be large, some dexterous manipulation might force it on- 

 ward into the mouth. As it but seldom happens, however, 

 that our attention is drawn to it before its bulk is such as 

 to preclude the possibility of stirring it, we are in general 

 necessitated to incise the duct in order to extract it. And in 

 making our incision, we are to do it cautiously, in the 

 direction of the canal, from one extremity to the other of 

 the tumor ; and, as soon as we have extracted the calculus, 

 either with our fingers or forceps, take special care to ap- 

 proximate the lips of the wound and retain them in appo- 

 sition by some adhesive plaster, lest we incur the consequences 



