KFFECTS OF MAGNESIA ON DHIC ACID. 
79 
he again sufiered pain in the region of the kidneys, and voided 
much sand, composed of uric acid, with ammoniaco-magnesian 
phosphate. He now took three half pints of soda water daily, 
which materially increased the proportion of the triple phos- 
phate, while that of uric acid was considerably diminished. 
Ten drops of muriatic acid were then taken three times a day Exhibition of 
in water. The red sand now began to re-appear, and on the 
4th of February, he voided a very small uric calculus. The 
urine made after dinner contained more or less mucus, streaked 
with blood, a symptom which was much aggravated by a slight 
excess in wine. On the Cith, he left London, and employed no 
medicine until the 12tb, when he returned, in consequence of 
having voided a large quantity of the white sand. 
Having observed the efficacy of carbonic acid in preventing 
the deposition of the phosphates, and having found it less liable 
than any other acid to induce a return of the uric gravel and 
calculi, I now directed him to take half a pint of water, highly 
impregnated with fixed air, four or five times a day, and to 
drink cider instead of wine. On the 1 8th of February, his 
urine was less turbid than it had been for some months before, 
and on the 20th of March, having continued the use of car- 
bonic acid, he had no remaining symptoms*. 
In August, his urine became again turbid, but by the use of 
vinegar and lemon juice at his meals, which acids, he now finds, 
have no tendency to induce a return of the red gravel, he suc- 
ceeds in preventing this symptom. 
Case 2, On the 11th of October, 1812, the operation for Case $. De’ 
stone in the bladder was performed upon a boy, eleven years 
age, and four calculi were extracted, of which the largest was phosphate, 
of the size of a small horse bean : they were each composed 
* I have several times examined the urine, vrifli a view to ascertain 
whether any of the acids which were exhibited, could be detected in 
that secretion; but tlie results of such experiments are so much inter- 
fered with by the very compound nature of the urine, that I have not 
hitherto been able to draw any satisfactory conclusions respecting 
them. 
of 
