204 DR. BENCE JONES ON THE SOLUTION OF URIC ACID CALCULI 
action was apparent on the calculus until the alkali was evolved from below. At five 
o'clock a voltameter interposed in the circuit showed that 2 cubic inches of mixed 
gases were produced in three minutes, but at this time the action of the battery was 
deduction could be made as to the influence of the different forms of the elec- 
Being anxious to know whether increased power of the battery and a better arrange- 
ment for keeping the temperature about that of the human body would be attended 
with advantage, another uric acid calculus was taken. It was very flat, and had been 
divided. The half used weighed 1074 g™ns. The electrodes were those used in the 
first experiments. The portions not in contact with the calculus were covered with 
glass. The negative electrode was on the external surface of the stone, and was 
below. The solution consisted of the same strength of nitre as before, but to three 
pints of the solution eight ounces of urine were added i this being taken as the largest 
quantity likely to be secreted during the time that the experiment was likely to be 
continued in the human body. The battery consisted of twenty pairs of Groves 
plates. By means of a siphon leading from the vessel in which the calculus was 
placed and by means of a reservoir with a stopcock, a continuous current of the 
Llutio’n was allowed to flow around the stone; thus the temperature could be most 
easily regulated. r .u w 
Experiment G.—The action began at O'- 28 -a.m., the temperature of the solution 
then being 64°. . . , i j 
At 9’’ 55“ A.M., the voltameter showed that 1 cubic inch of mixed gases was evolved 
in thirty-five seconds. 
The action was stopped at 12*' 45™. 
Total time 3*“ 17”'- 
The calculus when dry weighed 80 grains, so that the loss was 27^ grains in three 
hours and a quarter. There was a deep red stain on the calculus when it was 
removed from the solution ; this increased on drying, but it was more marked at the 
negative than at the positive electrode. The calculus was partially cut m halve^. 
(See fig. 3.) On the negative electrode there was a deposit, which, when scraped ofl 
and examined, proved to be earthy phosphate, probably a deposit from the urine. 
The calculus itself on the surface, near the negative electrode, was made white from 
a slight deposit of earthy phosphate. 
The current of the solution of nitre was continuous throughout, and the tempe- 
rature was kept between 90° and 106°; when the action was stopped, the fluid was 
still slightly acid from the urine which was originally added. 
No other experiments were made with uric acid calculi, so that no deductions have 
to be made for unsuccessful experiments. 
