28 
Mr. Children on some alvine concretions 
under an exhausted receiver, it sunk readily in that fluid. 
The calculus selected by Sir Everakd Home for analysis, 
was divided by him, and the plum stone nucleus cut through 
as in the other. The unequal distribution of their component 
parts, renders it impossible that the results of any two 
analyses should agree very accurately in the relative propor- 
tions of the several ingredients of the concretions ; there is 
no difficulty, however, in ascertaining their nature. They con- 
sist of phosphate of lime and ammoniaco-magnesian phos- 
phate, the former in very much the largest proportion ; of 
a large portion of animal matter, principally gelatine ; a small 
portion of resin, and a fine fibrous vegetable substance, from 
the inner coat enveloping the farina of the oat, which, when 
the outer husk is removed, is seen to consist of a number of 
delicate fibres arranged longitudinally round the farina. I 
did not discover any fatty matter, either by the action of boil- 
ing water or a weak alkaline solution, nor any of the sub- 
stances usually found in urinary calculi, except the phosphates 
already mentioned. 
The method I adopted for the chemical examination of the 
calculus, was, by submitting it successively, ( 1) to the action 
of cold water; (2) of boiling water; (3) of alcohol; (4) of 
a dilute solution of caustic soda; and (5), of muriatic acid. 
The cold aqueous infusion exhibited no decided trace of al- 
bumen, either on being boiled, or by the test of corrosive 
sublimate. Sulphate of silver, muriate of baryta, and oxalate 
of ammonia rendered it slightly turbid. By the second and 
fourth processes I obtained animal matter, consisting chiefly 
of gelatine. Its solution in water passed very slowly through 
the filter whilst cold, more readily when hot. It was not 
