Magnesia in Calculous Complaints, 1 3 



After a further continuance of the use of the magnesia 

 for three weeks, the urine was often much loaded with 

 uric acid and mucus; but these appearances, which before 

 the use of the magnesia were constant, are now only occa- 

 sional, so that the disposition to form a redundant quan- 

 tity of uric acid is much diminished: it is also deserving 

 of remark, i:.at there has not been the slightest symptom 

 of gout from the time of the last attack, winch is more 

 than a year back, alo'riger interval of ease than this patient 

 has experienced for the last six years. 



He has now omitted the regular use of the magnesia; 

 but on perceiving any unplca-ant. sensation in the stomach, 

 he returns to it for a week or ten days, and then again 

 J eaves it off. 



From the preceding cases it appears, that the effects of 

 magnesia taken into the stomach, are in many respects difr 

 ferent from those produced by the alkalies, in those patients 

 in whom there is a disposition to form a superabundant 

 quantity of uric acid. 



With a view to ascertain their comparative effects on 

 health v urine, when taken under the same circumstances, 

 {he following experiments were made. 



Experiment 1. On Soda. 



Two drachms of subearbonate of soda were taken on 

 an empty stomach at nine o'clock in the morning, dis- 

 solved in three ounces of water, and immediately after- 

 wards, a large cup of warm tea. 



In six minutes, about one ounce of urine was voided ; 

 jn twenty minutes six ounces more; and after two hours, 

 a similar quantity. 



The first portion became very lurbid, within ten minutes 

 after it had been voided, and deposited a copious sediment 

 of the phosphates, in consequence of the action of the al- 

 kali upon the urine. It slightly restored the blue -colour to 

 litmus paper reddened with vinegar: the alkali, therefore. 

 was not merely in sufficient quantity to saturate the un- 

 combined acid in the urine, and consequently to throw 

 down the phosphates; but it was in excess, and the urine 

 was voided alkaline. 



The urine voided after twenty minutes, also deposited h. 

 cloud of the phosphates ; but the transparency of that void- 

 ed two hours after the alknli had been taken, was not drs* 

 turbed. 



Here, therefore, the effect of the alkali upon the urine, 

 veas at its maximum, probably in less than a quarter of an 



hour 



