Magnesia in Calculous Complaints, 15 



large doses, neither produces so rapid an effect upon the 

 urine, nor so copious a separation of the phosphates, as the 

 alkalies ; on this its value as a remedy in calculous dis- 

 orders seems materially to depend. 



Experiment 4. On Lime. 



Two ounces of lime water, taken in the morning upon 

 an empty stomach, with a cup of milk and water, pro- 

 duced no effect whatever. 



A pint of lime water, taken at four intervals of an hour 

 each, produced a slight deposition of the phosphates at the 

 end of the fifth hour. The urine voided at the third hour 

 was not at all affected ; at the fifth hour, the effect appeared 

 at its height, but was not nearly so distinct as from small 

 doses of soda, notwithstanding the insoluble compounds 

 which lime might be expected to form with the acids in 

 the urine. 



The unpleasant taste of lime water, the quantity in which 

 it requires to be taken, on account of the small proportion 

 of the earth which is held in solution, and the uncertainty 

 of its effect, are circumstances which render it of little use, 

 excepting in some very rare cases, where it has been found 

 to agree particularly well with the stomach. 



The effect of carbonate of lime upon the urine was much 

 less distinct than that of lime water: at times it produced 

 no effect, but when taken in very large doses, a slight de- 

 position of the phosphates was produced. 



These experiments were repeated upon three different 

 individuals, and there was always an uniformity in the re- 

 sults. 



When the medicines were taken some hours after food 

 being received into the stomach, their effects upon the 

 urine were retarded, but not prevented. 



The effects of many other substances upon the urine 

 were examined into during this investigation ; but they 

 varied so much according to circumstances, that no satis- 

 factory results were produced. 



As it is found in the foregoing experiments, that the 

 effects of soda on the urine are modified by the presence of 

 carbonic acid, the following experiment was made, to as- 

 certain whether any sensible effects are produced by that 

 acid on healthy urine. 



Twelve ounces of water very highly impregnated with 

 carbonic acid, were taken upon an empty stomach at nine 

 o'clock in the morning. At ten o'clock about eight 

 ounces of urine were voided, which had a natural appear- 



ance. 



