The third was a gentleman of 43, who had passed three small cal-
culi, and whose urine had for a short time been constantly turbid,
and occasionally deposited red sand.
By the use of soda-water, these symptoms were diminished, but returned in some degree even during the continued use of it; and his urine became also loaded with mucus.
By taking twenty of magnesia every night, the uric acid diminished in quantity, but did not disappear entirely, even by the continued use of magnesia for three weeks in the same quantity. It was then repeated.every night and morning for a month, and suc- ceeded in restoring the urine to a perfectly healthy state. Upon a return of the disorder, he had recourse again to the magnesia, with the same effect.
The fourth patient was subject to gout, and occasionally voided abundance of red sand, consisting of uric acid. He was subject to heart-burn, and to other pains attendant upon weakness of stomach, for which he had been in the habit of taking tincture of bark and other spirituous medicines. He had also tried the use of alkalies, but could not continue them on account of the unpleasant sensation they occasioned in his stomach.
Magnesia was accordingly given, at first three times a day, and afterwards in a quantity of twenty grains twice every day; and it had the efi'ect of lessening the disposition to form uric acid, and appeared also at least to suspend the attacks of gout for a greater length of time than he had been accustomed to.
Comparative trials were afterwards made of the effects of the alkalies and of magnesia upon healthy urine.
Two drachms of subcarbonate of soda seemed to Mr. Brande to produce its full effect upon the urine in a quarter of an hour after it had been taken, occasioning a precipitation of the phosphates of lime and magnesia, and giving other indications of its presence, by restoring the blue colour to litmus-paper.
When supersaturated carbonate of soda was taken, the precipitation of the phosphates was less distinct and less rapid, as they remained dissolved for some time by excess of carbonic acid in the urine. and then began to appear as a pellicle at the surface by gradual escape of the carbonic acid in the form of gas.
In experiments with potash, the results were the same as when soda was employed.
Magnesia had also the same effect of occasioning a precipitation of the earthy phosphates; but on account of its insolubility, a greater length of time was required to produce the effect.
Lime-water also required as much as five hours to produce a sensible precipitation: and even then it was not nearly so distinct as from the alkalies.
Since the effects of soda or potash were altered by the presence of carbonic acid, the acid itself was tried alone, by taking twelve ounces of water highly impregnated with carbonic acid; and as it evidently passed off by the kidneys, and appeared in the urine of a healthy
