438 MORBID PRODUCTS. 



3, urate of soda ; 4, urate of magnesia ; 5, urate of lime ; 

 6, benzoate or hippurate of ammonia ; 7, oxalate of lime ; 

 8, oxalate of ammonia ; 9, uric or xanthic oxide ; 10, cystin ; 

 11, neutral and basic phosphate of lime; 12, ammoniaco-mag- 

 nesian phosphate ; 13, carbonate of lime ; 14, carbonate of 

 magnesia; 15, fibrin; 16, silica, t Mixed with these consti- 

 tuents we likewise meet with fat, extractive matters, albumen, 

 vesical mucus, and peroxide of iron. 



Of these constituents those numbered 1, 2, 7, 11, 12, are 

 the most common, and occur in the largest quantity; those 

 numbered 3, 4, 5, 13, 14, 16, are not of rare occurrence, but 

 are usually met with in very small quantity in calculi composed 

 of other ingredients. Uric oxide (9) has been only observed 

 in three [four] cases ; and cystin is by no means common. 



Fibrin was once noticed by Marcet as a constituent of an 

 urinary calculus, but Berzelius is inclined to suppose that in 

 reality it was vesical mucus. 



The presence of benzoate or hippurate of ammonia in urinary 

 calculi, recorded by Brugnatelli, and of oxalate of ammonia, 

 described by Devergie, is scarcely compatible with the great 

 solubility of these salts. 



The following points respecting the physical character of 

 urinary calculi are deserving of notice : 



The form varies in accordance with the seat of origin and 

 the chemical composition ; the oval or spheroidal is the most 

 frequent; round calculi are often compressed laterally, and 

 renal concretions sometimes assume a polygonal or even a 

 branching coralline form; in the ureters cylindrical calculi with 

 prominences and depressions have been described. The sur- 

 face is smooth, and presents few irregularities in calculi of uric 

 acid ; it is flat and more or less rough in many phosphatic 

 calculi; earthy and easily triturable in urate of ammonia calculi; 

 tuberculated, as we sometimes observe in calculi of uric acid, 

 the urates or cystin; or armed with prominences and asperities 

 in the oxalate of lime calculi. 



The colour of these concretions varies for the most part from 

 a pale yellow to a yellowish-red, brown, or brownish-green. 



Calculi of the earthy phosphates are colourless, or nearly so ; 



1 [To these Heller has recently added urostealith.] 



