450 MORBID PRODUCTS. 



Basic phosphate of lime or bone-earth never occurs as the 

 sole constituent of an urinary calculus ; the same is the case 

 with ammoniaco-magnesian phosphate. 1 



IX. Calculi of carbonate of lime. Calculi consisting merely 

 of carbonate of lime and animal matter are somewhat rare. 

 Smith found 18 such calculi in the bladder of a young man, 

 and Brugnatelli mentions 48 pisiform concretions of the same 

 nature taken from a young man, and 16, the size of a nut, from 

 a woman. According to Berzelius they are generally white or 

 gray, but sometimes yellow, brown, or red; the tint depending on 

 the animal matter. The formation of these calculi is due to an 

 alkaline condition of the urine, and to the absence of the ordi- 

 nary phosphates. On heating a fragment before the blowpipe, 

 it evolves an odour of burned bone, and readily burns white. 

 On treating the residue with hydrochloric acid eifervescence is 

 observed, unless the heat has been very intense and prolonged, 

 in which case the carbonate is converted into caustic lime, and 

 it dissolves without effervescence : in this case it is also soluble 

 in water and forms an alkaline solution. If a fragment of the 

 unheated calculus is pulverized and treated with dilute hydro- 

 chloric acid, it dissolves with effervescence and leaves a residue 

 of vesical mucus. 



Although it seldom occurs as the principal ingredient, it is 

 often found associated with other constituents, especially with 

 phosphate of lime, in urinary calculi. 



I have examined two yellow calculi of the form and size of 

 a pea, taken from the kidney ; they consisted of carbonate and 

 phosphate of lime. Proust also mentions vesical calculi com- 

 posed of carbonate and phosphate of lime. Prout was the first 

 who detected carbonate of lime in urinary calculi : it was in 

 that instance associated with phosphate of lime and traces 

 of urate of lime. Walther describes six calculi in which the 

 nucleus was urate of ammonia, while the cortex was com- 

 posed of carbonate and phosphate of lime. Prout mentions a 

 mulberry calculus in which the external layer was soft and con- 

 sisted of oxalate and carbonate of lime, the second of carbonate 

 and phosphate of lime, and the third of phosphate of lime. 



1 [A human calculus composed entirely of ammoniaco-magnesian phosphate is de- 

 scribed by Scharling, ' On the Chemical Discrimination of Vesical Calculi/ translated 

 by Dr. Hoskins, p. 55.] 



