232 Mr. W. Brande on the Differences 
Four distinct substances are extremely rare in calculi ; I 
have seen one in which the uric acid, the ammoniaco-mag- 
nesian phosphate, the phosphate of lime, and the oxalate of 
lime, were all in perfectly separate and distinct layers. 
Four calculi, having the following extraneous substances 
for their nuclei were examined. 
1. A common garden pea. 
2. A needle. 
3. A hazle nut. 
4. A part of a common bougie. 
In the two first instances, the calculous depositions were of 
a pale gray colour, inclining to white ; soft and friable in their 
texture, and entirely soluble in muriatic acid. 
The composition of the first was as follows ; 
Grains. 
Phosphate of lime - - 65. 
Ammoniaco-magnesian phosphate - 28. 
Loss 7. 
100. 
Of the second ; 
Phosphate of lime - - 45. 
Ammoniaco-magnesian phosphate - 38. 
Oxalate of lime - - - 12. 
Loss 5. 
100.* 
The deposition of calculous matter upon the bougie was 
covered with blood, and in very small quantity, the bougie 
* It appears that in this case there had been an accidental disposition to the for- 
mation of oxalate of lime. 
