Concvcuicnt lu>niiatioii. 



227 



In the parts of the large intestine just mentioned there are also 

 found not infrequently hard, stony concretions {intestinal calculi, 

 enteroliths), ranging in weight up to eleven kilograms, looking 

 not unlike billiard balls or bowling balls, or sometimes of pyramidal 

 shape from being worn off on the sides. The main constituent of 

 these dense calculi is, according to Fiirstenberg and Gurlt, ammonio- 

 magnesium phosphate (over ninety per cent.), the precipitation of 

 which occurs especially in feeding wheat and rye bran (the horses 

 belonging to millers and bakers), such a food containing a large 

 amount of magnesium phosphate. This is dissolved in the acid 

 intestinal juice and in case of the development of ammoniacal com- 

 pounds unites with the ammonia to form the almost insoluble triple 



Fig. 40. 

 Half of a fractured laiiiellaterl enterolith from a horse. 



phosphate. The marked sluggishness of peristalsis which obtains 

 with this diet, and ammoniacal fermentation of the intestinal con- 

 tents by bacteria, aid in the formation of the calculi. Usually the 

 larger examples are single : but of the smaller sizes there may be 

 dozens or hundreds in one intestine. In addition to pressure ero- 

 sions caused in the mucous membrane by these calculi, they may 

 produce fatal results, especially by accidental impaction and ob- 

 struction at some narrow part of the intestinal tube. (For details 

 cf. SpczicUe pathol. Anatomic d. Haiisticrc, II. Aufl. 1902, Stutt- 

 gart, Enke's Verlag.) Horses which take in sand and mud in 

 drinking from pools (and the same is true of hogs from swallowing 

 ground while rooting) occasionally get large masses of such ma- 

 terial into the intestine and may as a result suffer from the forma- 

 tion of diverticula. 



