on the Effects of Magnesia. 358 
-appearance of the urine, had the same effect as the muriatic 
acid, 
As water impregnated with carbonic acid could not be 
procured, he was directed to dissolve, in separate portions 
of water, twenty grains of citric acid, and thirty grains of 
the crystallized carbonate of potash, and to take the mixed 
solutions, during the effervescence. This quantity was at 
first only taken night and morning ; but as 1t agreed per- 
fectly well, it was afterwards repeated four and five times 
daily. Under these circumstances the appearance of the 
urine was soon improved, and both the mucus and the sand 
were considerably diminished in quantity. In six weeks 
the urine, when voided, was transparent; but a consider- 
able deposition of the phosphates took place, when it had 
remained for some hours at rest. In this state be left Lon- 
don, and has since informed me, that the sediment gradually 
diminished under the use of the carbonic acid, that his 
urine is never turbid, and that the irritation in the bladder 
has entirely subsided. 
It did not appear necessary to detail the minutiz of the 
ahove cases; they have been selected with a view to eluci- 
date the treatment of the disease, as far as it depends upon 
chemical principles, and to furnish the data upon which the 
following conclusions are founded. 
_ 1. That where alkalies fail to relieve the increased secre- 
tion of uric acid, and to prevent its forming calculi in the 
kidneys, or where they disagree with the stomach, magnesia 
is generally effectual, and that it may be persevered in for a 
considerable time without inconvenience, where the ten- 
dency to form excess of uric acid remains. 
2. When the alkalies, or magnesia, are improperly conti- 
nued, after having relieved the symptoms connected with 
the formation of the red sand, or uric acid, the urine ac- 
quires a tendency to deposit the white sand, consisting 
of the ammoniacormagnesian phosphate and phosphate of 
lime, 
3. The mineral acids (muriatic, sulphuric, and nitric,) 
diminish, or entirely prevent the deposition of the phos- 
phates; but are apt to induce a return of the red gravel. 
4. That vegetable acids, especially the citric and tartaric, 
are Jess liable to produce the last mentioned effects, even 
when taken in large doses for a long time; and that car- 
bonic acid is particularly useful in cases, where the irritable 
state of the bladder prevents the exhibition of other re- 
medies. 
Z2 LIX. Notes 
