172 DISEASES OF THE DIGESTIVE APPARATUS. 



muddy food ; also, that observed in famished army horses, and in 

 animals addicted to the habit of eating earth, are classified in the 

 same group. 



Deglutition of hair during shedding may cause balls and con- 

 cretions (segagropilse), which produce disorders similar to those 

 occasioned by calculi. » Other foreign bodies swallowed (pieces of 

 cloth, needles, etc.) produce these accidents more rarely. 



Intestinal calculi, properly speaking, consist principally in a 

 deposit of ammonio-magnesium phosphate (90 per cent,, as stated 

 by Fiirstenberg), to which are added lime phosphates, phosphates 

 of magnesia and silica, the different chlorides, some traces of iron^ 

 and organic matters (mucus, epithelium, alimentary substances). 

 They are formed at the expense of the phosphate of magnesia, with 

 which the bran is particularly loaded, and which is added to the 

 ammoniacal compounds of the intestinal contents. These originate 

 from the atmosphere of the stables, and are introduced into the 

 digestive canal by the intermediary of the drinking-water. A 

 phosphate of insoluble base is thus formed in the stomach. The 

 starting-point of the precipitation is generally a foreign body, a 

 particle of sand or oats, around which the basic phosphate deposits 

 are continually accumulating. 



Gastric calculi are intestinal calculi brought back into the stomach 

 by the anti-peristaltic movements. They could not be formed in 

 the stomach itself, on account of the acid reaction of its contents, 

 and because of the short time the alimentary matters remain 

 there. 



Calculi are ordinarily formed in the large intestine, especially in 

 the larger curve of the colon, more rarely in the caicum. In 900 

 autopsies, Colin found calculi 23 times in the large curvature of 

 the colon, and only once in the caecum. 



Local alterations produced by the various intestinal concretions 

 are the same as those which complicate the obstruction through 

 alimentary stagnation. 



The precise diagnosis is to be drawn from the process of evacu- 

 ation of these products, or from their direct detection through 

 rectal exploration. In horses consuming large quantities of bran 

 for a long period, and which suffer frequently from colic (millers' 

 horses), we must always consider the probable existence of calculi, 

 notwithstanding the frequency of colic from overloading of the 

 stomach in these animals. 



