, or else, in combination with
soda and ammonia, as an amorphous "brick-dust" deposit, which, on
cooling, leaves a red stain on the bottom of the vessel, soluble in hot
water. These substances are derived from the disintegration of
nitrogenized food taken in excess of demand, and from the breaking down
of the human tissues. They occur therefore in fevers, in wasting
diseases, and in the normal subject after excessive muscular exercises,
especially if these exercises have been accompanied with so much
perspiration that the excess of water from the blood has escaped by the
skin rather than by the kidneys. The abundance of this deposit is in
accordance with the amount of heat developed and work done in the body,
and corresponds with the dust and ashes raked out of the fire-box of the
locomotive after a long run. But supposing that the uric acid debris
continues to be excessive, the risk of the formation of renal or vesical
calculi becomes considerable, and it may be advisable to place the
patient on a restricted nitrogenized diet, to induce him to drink large
quantities of water, and to keep his bowels so loose with watery
laxatives, such as Epsom salts or sulphate of soda, that the waste
products of his body are made to escape by the bowels rather than by the
kidneys. In addition to the salts just mentioned, an occasional dose of
blue pill will prove helpful. A course of treatment at Contrexeville or
Carlsbad may be taken with advantage.

Alkaline urine is unable to hold the phosphates of ammonia and magnesia
in solution, so they are deposited in abundance either in the kidney or
bladder. If the voided urine is allowed to stand in a tall glass they
sink to the bottom with pus and mucus in a cloudy deposit. To remedy
this condition it is necessary to treat the cystitis with which the
bacterial decomposition of the urine is associated. It may be that a
calculus of acid urine, such as one of uric acid or oxalate of lime, has
been resting in the bladder and keeping up incessant irritation, and
that the micro-organisms of decomposition or suppuration have found
their way to the mucous lining of the bladder from either the bowel, the
urethra or the blood-stream; undergoing cultivation there they break up
the urea into carbonate of ammonia and so render the urine alkaline.
This alkaline urine deposits its phosphates, which light upon the
calculus and encrust it with a mortary shell, which may go on increasing
in size until it ma