350 Additional Observations 
weighing nine grains. For several successive 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 fer- 
mented 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 reco- 
ver, 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 re- 
ceiving any benefit, he was induced to make a trial of mag- 
nesia, of which he took one tea-spoonful night and morn- 
ing in cold chamomile tea. In about a week, the state of 
his stomach was much improved, and the deposit in the 
urine proportionally diminished, and in three weeks every 
symptom of disease had disappeared. 
In February 1812, 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 
produced no good effect, and that alkalies materially aggra- 
vated his complaint, by disagreeing with the stomach and 
_greatly increasing the urinary deposit. 
On examining the sand, I found that instead of consist- 
ing as formerly of uric acid, it was composed of a mixture 
of the ammoniaco-magnesian phosphate with phosphate of 
lime: he was directed to abstain from magnesia and alkalies, 
and to adopt a plan of treatment which it is the object of 
the second section of this paper more particularly to ex- 
plain. 
The foregoing is a well marked case of uric gravel with a 
strong tendency to form calculi, materially relieved by the 
use of alkaline remedies: it illustrates their usual effects 
when carelessly persevered in, and shows the advantage 
with which magnesia may in such instances be erie 
it also exhibits the effect of magnesia and the alkalies, in 
producing the deposit of white sand (or phosphates) in the 
urine, when the red sand (or uric acid) has been removed. 
The cases which follow are selected, from among others, 
to explain the best mode of preventing the formation of 
white sand, and to show the most effectual treatment 
where it is a natural deposit in the urine, or where i 
een 
