Coitcrcnioit Poiinatioii. 



225 



particles of food within llicni may excite inflammatory changes, and 

 give origin to hihary colic from the s])asm and inllammation of the 

 muscular wall of the bladder; and it is possible that rupture of the 

 latter may occur. 



Salivary Calculi (calculi salii'ulcs). — Small concretions and cal- 

 culi are formed from the calcium salts of the secretion (calcium 



ry 



Fig. 38. 

 Sectioned surface of a gall stone of a cow. (After Trolldenier. ) 



carbonate and phosphate) and from carbonate of magnesium, potas- 

 sium and sodium in the ducts of the oral salivary glands (parotid, 

 sublingual and submaxillary) and of the pancreas (abdominal 

 salivary gland). These concretions are usually chalky. In the 

 horse salivary calculi sometimes form in Steno's duct to the size 

 of a goose egg (200 to 600 grams in weight), often having as a 

 nucleus a bit of chaff, a piece of straw or an oat seed, which has 

 in some way gotten in from the mouth. According to Galippe 

 bacteria by inducing fermentative changes in the saliva seem to 

 be the occasion for the separation of the salts. 



