CHAPTER LXI. 



SPOEADIC DISEASES— continued. 

 LOCAL DISEASES— continued. 

 (0.) DISEASES OF THE BOWm.S—contmued. 

 INTESTmAL CONCEETIONS. 



The common seat of the various concretions is found to be in 

 the large intestines, where they sometimes attain a large size, 

 and as much as twenty-five pounds or more in weight. Occa- 

 sionally, but very rarely, they have been found in the stomach 

 weighing four or five pounds. 



They were studied by the late Professor Morton, and classified 

 under three heads, namely, 1st. Phosphatic calculi ; 2d. Oat-haii 

 calculi ; and 3d. Mixed calculi. 



1st. Phosphatic Calculi. — These are hard, smooth, and polished 

 on their external surface, bearing much resemblance to a common 

 pebble. If a section be made of a phosphatic calculus, it will 

 be found to consist of concentric layers arranged around a nucleus, 

 generally consisting of a piece of iron or stone. If several of 

 them, or any other form of calculus, be formed together, they 

 are generally flattened upon their sides, or concave on one side 

 and convex on the other, the convexity of one stone fitting into 

 the concavity of another, and so on. This form of calculus is 

 now much more rarely met with than formerly. This arises 

 from the circumstance that the food of animals is much better 

 prepared and cleaner than it used to be, and containing, there- 

 fore, fewer accidental materials or foreign bodies, which formed 

 the nuclei 



Their chemical composition, according to Girardin, is aa 

 follows : — 



