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Observations on the Effects of Magnesia, in preventing an increased 

 Formation of Uric Acid ; with some Remarks on the Composition of 

 the Urine. Communicated by Mr. William T. Brande, F.R.S. to 

 the Society for the Improvement of Animal Chemistry, and by them 

 to the Royal Society. Read February 22, 1810. [Phil. Trans. 1810, 

 p. 136.] 



Mr. Home's inquiries into the functions of the stomach, and his 

 discovery of liquids passing directly from the cardiac portion into the 

 circulation of the blood, occasioned him to considejr the prevention of 

 calculous complaints, by correcting the generation of acid in the sto- 

 mach, and consequent secretion of uric acid. 



Since magnesia was better adapted to the mere correction of acidity 

 than alkalies, as it could not be absorbed till it had been previously 

 dissolved, Mr. Home was desirous of examining its effects in pre- 

 venting the generation of uric acid, and requested Mr. Brande's as- 

 sistance for that purpose. 



After several previous trials, in which it appeared that an excessive 

 secretion of uric acid was corrected by magnesia more than by a 

 liberal use of alkalies, it was afterwards tried in various cases of con- 

 firmed calculus ; and four cases are selected as instances of the prin- 

 cipal varieties of that disorder, from many others in which magnesia 

 was tried. 



The first was that of a gentleman of 60, who had passed small 

 calculi of uric acid. 



He had first taken subcarbonate of soda in water highly impreg- 

 nated with carbonic acid, to the quantity of nine drachms in a day, 

 but without any apparent effect on the secretion and formation of 

 uric concretions. 



He then took, in the same manner, subcarbonate of potash, dis- 

 solved in water impregnated with carbonic acid, to the quantity of 

 three drachms every day ; but though the deposit of sand from the 

 urine was in some degree diminished, yet small calculi continued 

 occasionally to be voided. 



On the contrary, by taking as much as fifteen grains of magnesia 

 three times a day, the quantity of uric acid was diminished in quan- 

 tity ; and after three weeks was only occasionally perceived in his 

 urine. 



The second case is that of a gentleman 40 years of age, who for 

 four years preceding had occasionally passed much red sand, and 

 once a small calculus. 



Subcarbonate of soda was first given him in water highly impreg- 

 nated with carbonic acid, which had the effect of diminishing the 

 secretion of uric acid, but not of preventing occasional severe attacks 

 after irregularities in his diet. 



Magnesia was next directed, to the quantity of twenty grains every 

 night and morning ; and during six weeks' continuance of this pre- 

 ventive, he had no return of his complaint, and no superabundance 

 of uric acid in the urine. 



