‘852 Additional Observations 
much sand, composed of uric acid, with ammoniacoe 
magnesian phosphate. He now took three half pints of 
soda water eaey , Which materially increased the proportion 
of the triple phosphate, while that of uric acid was con- 
siderably diminished. Ten drops of muriatic acid were 
then taken three times, a day 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 sym- 
ptom which was much agyravated by a slight excess in 
wine. On the 6th he left London, and employ ed no me- 
dicine until the 12th, when he returned in consequence of 
having voided a Jarge quantity of the white sand. 
Having observed the efheacy of carbonic acid in prevent- 
ing the deposition of the phosphates, and having found it 
Jess 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 cyder instead of wine. On the 
18th of February his urine was less turbid than it had been 
for some months before, and on the 20rh of March, having 
continued the use of carbonic 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, be 
now finds, have no tendency to induce a return of the red 
gravel, he succeeds in preventing this symptom. 
Case 2. On the 1)th of October 1812, the operation for 
stone in the bladder was performed upon a boy eleven 
years of age, and four calculi were extracted, of which the 
largest was of the size of a small horse bean: they were 
each composed of a nucleus or centre of uric acid, upon 
which the ammoniaco-magnesian phosphate was deposited. 
After the operation, the urine deported a large quantity 
of white sediment, and some small pieces of red gravel were. 
occasionally adele He was now directed to take eight 
grains of citric acid dissolved in barley water, three times 
daily ; under this treatment the sediment in the urine was 
considerably diminished, but did not wholly disappear. The 
dose of the acid was gradually increased to twenty grains, 
by which means the sediment was only occasionally depo- 
sited, and consisted of little else than mucus. Jt was ob- 
* | have several times examined the urine, with a view to ascertain 
whether any cf the acids which were exhibited could be detected in that 
secretion; but the results of such experiments are so much interfered with 
by the very compound nature of the urine, thai 1 have not hitherto been 
able to draw any satisfactory conclusions respecting them, 
served, 
