PRODUCTS, ADVENTITIOUS. 



faeces, to be readily soluble in sulphuric and 

 hydrochloric acids without effervescence. 



Crystals discoverable during life in connec- 

 tion with acknowledged states of disease may 

 be provisionally arranged as follows : 



Crystals t 



(a), Natural secretions 

 and excretions al- 

 tered in properties 



, Products of in- 

 flammation 



(c), Specific fluids of 



(</), Adventitious For- 

 mations.., 



forming in 



I Urine, 



1 Faeces, &c. 



Plastic"! , 

 o > exudations, 



Serous J 



Gangrenous products, 

 Catarrhal discharges. 



f Vaccinia, 



I Variola, 



1 Syphilis, 



l^ Glanders. 



f Cancer, 



\ Acephalocysts, &c. 



Of the natural secretions which (in conse- 

 quence of alteration in their composition) are 

 liable to contain saline matters in the form of 

 minute crystals, the urine is by far the most 

 important. With the strictly crystalline variety 

 may be associated certain amorphous pulveru- 

 lent precipitates. These products occur in 

 the urine in the form ofpe/licle, cloud, or sedi- 

 ment ; in other words, they form a thin stra- 

 tum on the surface of the fluid, float between 

 the upper and lower surfaces, or gravitate to 

 the bottom of the containing vessel. These 

 varying positions, appreciable to the naked 

 eye, aid the observer in forming a rough esti- 

 mate of the nature of the saline matter, and 

 may be almost conclusive on the point. The 

 microscopical and chemical characters com- 

 bined supply, however, the real evidence from 

 which their composition is ascertained* ; in 

 order to avoid repetition, we will defer the 

 consideration of these characters until engaged 

 with the subject of urinary calculi. We shall 

 have occasion to recur, in describing the mor- 

 bid substances (b, c, cT), referred to in the 

 above classification, to the appearance of 

 crystals within them. But it may be stated 

 here, as a general fact, that as the materials of 

 all such crystals exist primarily in solution, 

 and as absorption, evaporation, or chemical 

 appropriation of water leads to their deposi- 

 tion in the crystalline form, there is a source 

 of fallacy in the examination of preparations 

 kept in spirits ; certain salts, combined with 

 the aqueous part of the material examined, 

 are deprived of their water by the alcohol, 

 and separate in crystalline forms. 



2. Masses. Adventitious products be- 

 longing to the present sub-class, and possess- 

 ing sufficient bulk to be called masses, form 



* As the majority of the substances included 

 under the present head enter (though comparatively 

 in small quantity) into the composition of healthy 

 urine, it is necessary to observe that they, practi- 

 cally speaking, acquire the character of adventitious 

 products through the new form they assume, when 

 the proportion in which they accumulate increases. 



an important group, divisible into two series 

 differing from each other in a variety of im- 

 portant natural characters. Some of them are, 

 in truth, composed wholly or essentially of 

 saline or other non-plastic materials, precipi- 

 tated from the fluids of the system ; others of 

 similar materials, deposited in an adventitious 

 basis, itself stromal or non-stromal. In the 

 first series, the non-plastic compounds form 

 the essential, if not the whole, " materies 

 morbi;" in the second, these compounds are 

 merely superadded to pre-existing matter (com- 

 monly morbid) of another kind ; and such 

 superaddition, instead of increasing the ac- 

 tivity of functional disturbance in the system, 

 tends frequently to weaken the destructive 

 influence of that pre-existing matter. For the 

 sake of convenience, bodies belonging to the 

 first series may be termed true calculi, or sim- 

 ply calculi; to the second, pseudo-calculi, or 

 concretions. 



(A) CALCULI. True calculi, answering to 

 the definition just laid down, may be deposited 

 from almost all the secreted fluids. But of 

 these fluids, the urine is, perhaps, the only one 

 of which the saline and other actual constitu- 

 ents, independently of any materials naturally 

 foreign to their composition, form the sub- 

 stance of calculi ; when calculous formations 

 occur in other secretions, foreign ingredients 

 may almost invariably be detected. The saline 

 substance thus met with in calculous masses, 

 and which does not enter naturally into the 

 composition of the secretion, (or enters in 

 excessively small proportion,) is most com- 

 monly the phosphate of lime. So frequent is 

 the occurrence of this salt in calculous masses 

 on mucous surfaces, as to lead irresistibly to 

 the conclusion that mucous membrane has a 

 specific tendency to secrete this salt, under 

 certain conditions of local irritation. 



() Urinary calculi. Various constituents 

 of the urine are capable of accumulating indi- 

 vidually, or in association with each other and 

 with certain animal substances., (mucus, fibrin, 

 albumen, fatty matters, colouring matters, &c.,) 

 so as to form masses of variable form and size ; 

 these masses are according to their bulk 

 termed calculi, miliary calculi, and gravel. The 

 same materials unaggregated into masses form 

 the substance of sediments, clouds, and pellicles. 

 The following are the substances which to 

 various amounts have been recognized as the 

 constituents of urinary calculi : uric acid, 

 u rates of ammonia, of soda, of magnesia and 

 of lime, oxalate and benzoate or hippurate of 

 ammonia *, oxalate of lime, xanthin or uric 

 oxide, cystin, phosphate (neutral and basic) of 

 lime, triple phosphate of ammonia and mag- 

 nesia, carbonate of lime, carbonate of magnesia, 

 silica, peroxide of iron, fat, extractive matter, 

 colouring matters, fibrin, albumen, and mucus. 



The coalescence of the component parts of 

 urinary calculi is effected in three chief ways. 



* Simon remarks that the presence of the ben- 

 zoate, as recorded by Brugnatelli, and of the oxa- 

 late, as described by Devergie, is scarcely compatible 

 with the great solubility of those salts. 



