80 
EFFECTS OP MAGNESIA ON URIC ACID, 
of a nucleus or centre of uric acid, upon which the amnnonlaco- 
tnagnesian phosphate was deposited. 
After the operation, the urine deposited a large quantity of 
white sediment, and some small pieces of red gravel were 
occasionally voided. He was now directed to take eight grains 
of citric acid dissolved in barley water, three times daily j under 
this treatment, the sediment in the urine was considerably 
diminished, but did not wholly disappear. The dose of the 
Beneficial use acid was gradually increased to twenty grains, by which means 
of citric acid, jjjg sediment was only occasionally deposited, and consisted of 
little else than mucus. It was observed, that whenever the 
citric acid was omitted, even for twenty-four hours, the sedi- 
ment was greatly increased, and this was constantly attended 
with frequent desire to make water, and other symptoms of 
uritation in the bladder. On resuming the use of the citric 
iscid, the sediment always disappeared, and the irritation of the 
bladder subsided, and this happened so frequently, that no doubt 
could be entertained of the influence of the medicine on the 
composition of the urine. 
This plan of treatment was continued for three monthsj at 
the end of that period, it was found that the urine had not the 
same disposition to deposit the phosphates as formerly j even 
when the medicine was omitted, the sediment was small in 
quantity, and not constant in its appearance. He was now 
directed to omit the use of the citric acid, and occasionally to 
eat oranges and other acid fruits. He continued this plan until 
the beginning of April, 1813 ; his urine was then quite clear, 
and he had no symptoms of disease. 
Cases. Of Case 3 . In the month of October, 1811, a gentleman, thirty- 
posit removed of age, informed me, that he had observed a whits 
by tlie careful deposit in his urine, during the whole of the preceding summer, 
use of acids. . ° 
He had taken considerable quantities of soda water, which he 
thought increased the sediment, and alkalies in any other form 
produced a very obvious aggravation of the complaint. 
His urine was at all times clear when voided ; but after a 
few hours, a white powder was observed to separate from it, 
and a hlrn of crystalline matter formed upon the surface. The 
former 
