82 Dr. H. V. Carter on the Composition of Urinary Calculi. [Dec. 12, 



out, is not only valuable, but that it is even more delicate than the 

 simply chemical method ; by it will be seen more clearly than before that 

 no urinary deposit long retains an unmixed character, and besides will 

 be gained a more accurate conception of the true character and structure 

 of these hurtful concretions. 



Particular attention has been given to the nature of their nuclei or 

 first-formed ingredients, for it was obviously desirable to ascertain the 

 material and mode of commencement of calculi; and the author re- 

 gards it as not the least interesting of his results to have determined the 

 very frequent presence of urates in a globular form at their very earliest 

 beginnings. Stones removed from adults as well as from children may 

 possess a nucleus thus formed, and to such origin may succeed all 

 varieties of calculous deposit. The next most common ingredient of the 

 nucleus is the oxalate of lime, and this, too, in a form not generally re- 

 cognized, viz. as large rhombic crystals ; frequently, however, octahedral, 

 oval, and dumb-bell forms are seen, as well as spheroidal bodies origi- 

 nating from the latter ; these last-named structures are very charac- 

 teristic. The nucleus of a calculus was comparatively seldom found to 

 consist of uric-acid crystals. . 



Next in importance to the observation that globular and granular 

 urates very frequently compose the nucleus of all varieties of calculi, and 

 have commonly associated with them the oxalate of lime, is the evidence 

 elicited of the operation of known physical influences in determining the 

 form which these salts assume in connexion with stone. Reference is 

 made to the modifying influence of a colloid medium upon the process of 

 crystallization (as so admirably illustrated in Mr. Harney's well-known re- 

 searches) ; and it is here found that both urates and oxalates may present the 

 various stages of globular particles, complex globules, or spheroids, either 

 separate or blended, and laminae of varying thickness : there are evident 

 signs, too, that these structures undergo, at times, more or less disinte- 

 gration, which may be followed by a rearrangement of their molecules ; 

 and more especially does the calcic oxalate seem disposed to undergo 

 these changes, the resulting forms being highly characteristic. Neither 

 uric acid nor the phosphates were found otherwise than in a simpler 

 crystalline form ; the former, however, when liquor potassae is added, may 

 in combination be noticed to pass into minute globular particles, the 

 urate of potash being seen hi the field of the microscope to assume some 

 of the characters of ordinary urates ; and phosphate of lime artificially 

 produced was also observed in the shape of dumb-bells and spheres. 



The author refers to the structure of Eaphides, agates, some shells, 

 &c, and concludes that urinary calculi should not be classed with ordi- 

 nary concretions or mere mineral masses ; it is not, however, evident that 

 the animal basis of calculous matter, essential ingredient though it be, 

 presents or retains a strictly cellular character. 



Some details respecting the source and other characters of the calculi 



