on the Effects of Magnesia, 217 



considerable pain and difficulty, he voided a calculus com- 

 posed of uric acid, weighing nine grains. For several succes- 

 sive days his urine deposited a large quantity of red sand, and 

 three very small round calculi were voided. 



He was now directed to abstain from all kinds of fermented 

 liquors and sour food, and to take a pint of treble soda water, 

 ( containing three drachms of sub-carbonate of soda, ) daily. 

 Under this treatment he continued to recover, and remained 

 perfectly free from complaint until the end of August, when 

 a copious deposit of red sand appeared in his urine : he had 

 little pain in the affected kidney, but complained of almost 

 constant nausea, or want of appetite. The soda water was 

 increased to a pint and a half, and afterwards to two pints 

 daily, and in the intervals he drank very freely of barley 

 water. 



Having persevered in this way for ten days without receiv- 

 ing any benefit, he was induced to make a trial of magnesia, 

 of which he took one tea-spoonful night and morning in cold 

 chamomile tea. In about a week, the state of his stomach 

 was much improved, and the deposit in the urine proportion- 

 ally diminished, and in three weeks every symptom of disease 

 had disappeared. 



In February, 1813, having persevered in the use of mag- 

 nesia with little intermission, I was informed that the sand had 

 returned, that increasing the quantity of magnesia had pro- 

 duced no good effect, and that alkalies materially aggravated 

 his complaint, by disagreeing with the stomach and greatly 

 increasing the urinary deposit. 



On examining the sand, I found that instead of consisting 

 as formerly of uric acid, it was composed of a mixture of the 



