SALIVARY CALCULI 263 



dressing of styptic-colloid and covered with a thick pad of antiseptic wool 

 or absorbent lint. 



When necessary both should be renewed but not otherwise, and the 

 animal is to be so secured that he may not rub or otherwise disturb the 

 application. 



By some, closure of the wound is attempted to be brought about by the 

 production of a scab, and for this purpose it is freely dressed with caustic, 

 such as nitrate of silver, nitric acid, or the hot iron. 



In old-standing cases, where the wound has become callous and that 

 part of the duct near the mouth closed up and impermeable, the salivary 

 gland should be destroyed, and the formation and discharge of saliva from 

 it altogether arrested. This is accomplished by injecting some irritant 

 along the duct into the gland. For this purpose a solution of one of the 

 following drugs is employed, viz.: — Nitrate of silver, caustic ammonia, 

 or tincture of iodine. The immediate effect of this course is to cause in- 

 flammation and swelling of the gland, sometimes also the production of 

 an abscess; the ultimate result, however, is that the organ is spoilt, ceases 

 to secrete saliva, and wastes away. After this has been effected some 

 little defect in mastication will be observed for a short time, and it may 

 be that an attack of indigestion may follow, but with care in feeding and 

 management this will soon cease to be a matter of concern. 



SALIVARY CALCULI 



Although of rare occurrence calculi are now and again met with in the 

 course of the salivary ducts, and more especially in that one which conveys 

 the saliva from the parotid gland into the mouth. Salivary calculi are 

 of a grayish- white hue, very dense, and rough on one surface. When 

 existing alone they are rounded or elongated, but when two or more occur 

 together in the same duct they present a more or less irregular form owing 

 to the friction they exercise upon each other during the movement of the 

 jaws in mastication. Some specimens are very small while others (fig. 95) 

 reach several ounces in weight and four or more inches in length. The 

 longer calculi are usually somewhat concave on the side nearest to the 

 lower border of the jaw over which the duct passes. 



Chemically they are found to consist of carbonate and phosphate of lime 

 and a small quantity of animal matter. Carbonate of lime is the chief 

 constituent, and forms from eighty to ninety per cent of the whole. 



The formation of these stones is provoked by any obstructive cause 

 which prevents the escape and favours the accumulation of salivary fluid 

 in the duct, or by the entrance into it of small particles of grit or other 



