Intestinal Calculi. — Enteroliths. — Bezoars. 325 



The source of the magnesia may be found to a large extent in 

 the grains represented in the following table : 



Ash Mg. in Ash. 



Per cent. Per cent. 



Oat, grain 2.50 7.3 



Barley, grain 3.16 8.5 



Rye, grain 1.6 2.4 



Wheat, grain 2.12 9,98 



Wheat, bran 7.3 u.a 



Bean 3.1 6.6 



Pea 2.7 5.6 



The amount of magnesia in each of these grains is amply 

 sufiBcient to furnish the material for the constant growth of a 

 calculus. Wheat bran is preeminent in the amount of its mag- 

 nesia and therefore wheat bran has been charged with predis- 

 posing to calculi. In the perisperm as a whole, Fiirstenberg 

 found I per cent, of phosphate of magnesia, and in coarse bran not 

 less than 2.5 per cent. 



The ammonia which is essential to the precipitation of the 

 phosphate of magnesia in the form of the compound salt (am- 

 monio-magnesian) can be found wherever proteids are in process 

 of septic fermentation. The slightest failure to peptonize every 

 particle of such proteids, implies septic change and the evolution 

 of ammonia, which on coming in contact with magnesia phos- 

 phate instantly precipitates the insoluble salt. 



This fully agrees with the doctrine of the formation of urinary 

 calculi through the agency of bacteria,' since the ammonia is 

 essentially a fermentation or bacterial product. 



It may also be noted that the experiments of Rainey and Ord 

 showed that in the presence of colloids (mucus, epithelium, pus, 

 blood) the earthy salts are precipitated as minute globular bodies 

 which by further accretions become calculi. In the absence of 

 colloids the .salts tend to precipitate in angular crystalline forms, 

 so that the mulberrj- and coralline calculi may possibly have been 

 precipated in the absence of such bodies. From the solvent qual- 

 ity of ammonia, however, the contents may easily pass from a fer- 

 menting liquid containing colloids to a non-fermenting and non- 

 colloid mixture. 



The presence of a solid body which may act as a nucleus is an 

 essential element, and the condition of the food or drink will often 



