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 CHAPTER XII. 



SOLID MORBID PRODUCTS. 



Concretions. 



THESE morbid products are of frequent occurrence. They 

 are found in various, organs, especially in those through which 

 fluid glandular secretions are discharged. They then consist 

 for the most part of the most insoluble constituents of that fluid, 

 although they occasionally contain substances foreign alike to 

 the secretion and to the whole organism, and produced by a 

 depraved formative process. Concretions are, however, also met 

 with in other situations, as the brain, the cavities of the heart, 

 the arteries, &c. 



The substances ordinarily entering into the composition of 

 concretions are by no means numerous. Some concretions are 

 formed of one constituent alone, while others have a mixed 

 composition. The following substances must be viewed as true 

 formative constituents, not as mere accidental admixtures: uric 

 acid with its salts, uric oxide (xanthic oxide), cystin, hippurate 

 of ammonia, basic and neutral phosphate of lime, ammoniaco- 

 magnesian phosphate, oxalate of lime, carbonate of lime, car- 

 bonate of magnesia, fibrin, cholesterin, and biliphsein : the 

 accidental components are mucus of the urinary and gall- 

 bladders, albumen, hsematoglobulin, bilifellinic acid, fat, extrac- 

 tive matters, chloride of sodium, and lactate of soda. 



The principal object in the analysis of concretions is to de- 

 termine the nature of the leading constituents, and this may be 

 easily effected even by persons little skilled in chemical mani- 

 pulation. A blowpipe, a little platinum foil, and a few tests, 

 comprise all the requisite apparatus. 



Qualitative analysis of concretions. 



On heating a little of the concretion on platinum foil with 

 the blowpipe, three things may happen : the portion tested 

 may entirely disappear, or a part may disappear, while the rest 



