IN DIFFERENT SALINE FLUIDS BY THE AID OF ELECTRICITY. 
211 
are dissolved with difficulty, whilst calculi of oxalate of lime alone are acted on very 
slowly. 
Section III. On the Solution of Phosphatic Calculi and of Carbonate of Lime. 
Having found the solution of nitre so efficacious in its action on uric acid, and as 
it was at least as good if not better than any other solution in its action on oxalate 
of lime, it was most desirable that it should be found efficacious in its action on 
phosphatic calculi. 
Experiment 1 . — A piece of very hard phosphate of lime calculus, weighing 64 grains, 
was put into the nitre solution (one-fourth saturated solution and three-fourths distilled 
water). A battery of ten pairs of plates was first tried. 
The action began at 9^^ 15“ a.m. and was continued until 1 ^ 30“ p.m., the tempera- 
ture being between 68 ° and 106°. 
The action recommenced at 2 p.m. and was continued until 5 p.m., the temperature 
being between 70 ° and 106°. 
The total time was 7 ^ 15'”- 
The calculus when dry weighed 49 grains. Hence in seven hours and a quarter 
15 grains were dissolved. The solution took place chiefly at the part in contact with 
the positive electrode. 
Experiment 2 . — A divided fusible calculus, weighing 85 grains, was subjected to 
the action of a battery of twenty pair. The solution of nitre was the same as before, 
but to three pints of the solution eight ounces of urine were added, being the quantity, 
or more than the quantity which would be secreted during the time of the experiment. 
The action began at 9^ 2 /“ a.m. ; the temperature of the solution was 70°. 
The action was stopped at 10 ’^ 40“ a.m. ; the temperature was kept between 90° 
and 102 °. 
The total time was l'' 13“. 
The calculus when dry weighed only 54 grains, so that the loss in one hour and 
thirteen minutes was 31 grains. The current was continuous throughout. 
When the stone had been some time in the liquid, it was taken out with the elec- 
trodes still in contact. It then appeared that the stone had imbibed sufficient water 
to allow of the action going on through the wet stone without any liquid surrounding 
it. Hence probably the very rapid action which took place. 
The negative electrode was found to be coated with earthy phosphates. The solu- 
tion remained feebly acid throughout. 
The positive electrode was below in contact with the external surface of the calculus 
which was cut through. See fig. 4. 
On the Solution of Carbonate of Lime. 
Experiment 3. — A piece of marble, weighing I 70 grains, was put into the solution 
of nitre of specific gravity 1026. A galvanic battery of ten pairs of plates was 
employed. 
2 F 
MDCCCLITI. 
