on the Effects of Magnesia, 221 



In August his urine became again turbid, but by the use of 

 vinegar and lemon juice at his meals, which acids, he now finds, 

 have no tendency to induce a return of the red gravel, he 

 succeeds in preventing this symptom. 



Case 2. On the 11th 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 com- 

 posed of a nucleus or centre of uric acid, upon which the am- 

 moniaco-magnesian phosphate was deposited. 



After the operation, the urine deposited a large quantity of 

 white sediment, and some small pieces of red gravel vvere 

 occasionally voided. 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 deposited, and con^Jsted 

 of little else than mucus. It was observed, that whenever 

 the citric acid was omitted, even for twenty-four hours, the 

 sediment was greatly increased, and this was constantly at- 

 tended with frequent desire to make water, and other symp- 

 toms of irritation in the bladder. On resuming the use of the 

 citric acid, 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 months ; at 

 the end of that period, it was found that the urine had not the 



Oga 



