The second is an instance of the beneficial efl‘ects of magnesia in
correcting the formation of uric acid, where alkalies had relieved but
could not be continued. It also exhibits the prejudicial effects of both
when too long persisted in, by causing a redundance of an opposite
nature in the urine, and a consequent deposit of earthy phosphates
as white sand.
The object of the second section of this paper is to ascertain what acids may be employcd with most advantage in those cases where the ammoniacal phosphate of magnesia prevails in the urine, either naturally or by an injudicious use of alkaline medicines. For though the use of acids was pointed out fifteen years since by the same chemist who originally analysed this species of calculus, Mr. Brande is not aware that in the course of that time any experiments have been made to illustrate the mode of action of different acids.
The first case related is that of a gentleman who had been cut for the stone ten years before, and was again attacked with symptoms of calculus. By the use of a brisk purge in the first instance, one calculus was passed, but he still sufi'ered pain in his kidneys, that was aggravated by the use of soda water, which increased the pro- portion of triple phosphate in his urine. Ten drops of muriafic acid were then taken three times a day, which removed the white sand; but as this acid tended to increase the quantity of red sand, it was exchanged for carbonic acid, with decided relief to all the symptoms.
The second case was that of a boy, from whom four calculi had been extracted by the usual operation of lithotomy. These consisted principally of the triple phosphate of magnesia; and his urine con- tinued after the operation to be loaded with a deposit of this sub- stance, in the form of a white sand. The acid employed in this in- stance was citric acid, to the amount of twenty grains three times a day. As the effect of this remedy upon the disorder was found to be decisive, and the consequence of any omission was observable in less than twenty-four hours, it was persevered in for nearly three months, when the disposition to deposit the earthy phosphates was found to give ceased altogether, and the lad remained apparently free from ease.
Two other cases are also related: the first of which was relieved by citric acid taken twice every day, together with vinegar and other acid articles of diet; and the second by carbonic acid, taken as an effervescing draught, which prevented the formation of white sand, and removed an irritation of the bladder, occasioned by that deposit.
As the general results of these trials, the author infers,—
That where alkalies fail to correct the redundant secretion of red sand, magnesia is generally effectual.
That when either of these is improperly continued, they are liable to occasion the deposit of the earthy phosphates, in the form of white sand.
That the mineral acids prevent this deposition, but are apt to induce a return of red gravel, consisting of uric acid.
That vegetable acids, especially the citric and tartaric, are less
