230 NEW SOLVENT FOR STONE IN THE BLADDER. 
a solution of 1.6 grains of carbonate of lithia to two ounces 
of distilled water, afforded nine-tenths of a grain of uric acid. 
Thus is demonstrated the very superior solvent agency of 
the above feeble lithia solution over the Vichy water. 
Haifa grain of urate of soda (the ordinary basis of gouty 
concretions or chalk stones) diffused in an ounce of distilled 
water at the blood heat, completely dissolved with the ad- 
dition of one grain of carbonate of lithia, the solution con- 
tinuing limpid and unaltered; whereas, half a grain of the 
same urate, in a similar quantity of water at a corresponding 
temperature, rests apparently unchanged, as may be seen in 
the two phials before you. Urate of soda, as pointed out in 
my paper on Gouty Concretions, published in vol. xxiv. of 
the Medico-Chirurgical Transactions, is about as insoluble 
as uric acid. 
It deserves notice, that when fresh healthy urine is ren- 
dered alkaline by carbonate of lithia, no deposition ensues. 
A very large proportion of the stones which occur in the 
urinary bladder of man, are composed in whole or in part of 
uric acid. Of all the various menstrua hitherto recommend- 
ed, none appears to promise more favorably than the car- 
bonate of lithia, from the promptitude and energy with 
which in dilute solution it attacks calculi of this description. 
If, by means of injection,-we can reduce a stone at the rate 
of a grain or more an hour, as the above experiment would 
lead us to anticipate, we shall not merely diminish the posi- 
tive bulk of the calculus, but farther loosen its cohesion, 
disintegrate it, so to speak, causing it to crumble down and 
be washed away in the stream of the urine. Cases may 
present themselves in which it may be expedient to conjoin 
the use of the lithontriptor ; but only occasionally, and at 
long intervals. It is the frequency of repetition which ren- 
ders that instrument so hazardous. 
It may be presumed, moreover, that the plan of throwing 
in a weak solution of this kind, would generally exercise a 
beneficial influence in obviating irritation, by removing the 
