of Magnesia in Calculous Complain ts. 145 
was found to be the triple phosphate of ammonia and mag- 
nesia, and partly in the state of a white powder, consisting 
almost entirely, of the triple phosphate and phosphate of lime. 
The effect of large doses of magnesia, in producing a white 
sediment in the urine, is very commonly known, and has been 
erroneously attributed to the magnesia, passing off by the 
kidnies. 
These experiments, shew that magnesia, even in very 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 disorders seems ma- 
terially 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, produced 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, except- 
ing in some very rare cases, where it has been found to agree 
particularly well with the stomach. 
U 
MDCCCX. 
