This disorder consists in the deposition from the urine, within the body, of an insoluble sand-like matter. In health the urine carries off the results of the waste and disintegration of the tissues in a soluble state, but when these matters are in excess the urine frequently deposits them after being voided, on cooling. This often occurs after irregularities of diet, without actually being a morbid condition, but when the accumulation is excessive it causes a serious disease. The gravels are chemically either urates lithates, phosphates, or oxalates, according to the diathesis of the patient. The passage of gravel or renal calculi from the kidneys to the bladder through the ureters, causes the most excruciating pain. When anything in the bladder, as a mucous shred or a large gravel, acts as a nucleus, the constant accessions to this nucleus form what is known as stone in the bladder, which may be of various sizes.

In gravel the patient has a dull aching pain in the back, attended with urgent and frequent desire to urinate. Preceded by cutting or scalding pains in the urethra, neck of bladder, or in the course of the ureters. In stone we have the same symptoms, but the sudden stoppage of the stream during micturition is always suggestive of its presence in the bladder, and the patient has a constant desire to relieve the pain by pulling at the end of his penis.

TREATMENT. -- Diluents should be freely used, and a strict attention paid to diet. Animal food should be sparingly eaten, and alcoholic drinks totally avoided. The chemical nature of the gravel should be ascertained, and when this is done the chemical opposites administered. No treatment will avail, if not in chemical opposition to the diathesis of the patient. If medicinal treatment is ineffectual after a stone has been formed, the surgeon should be consulted, who will remove it by an operation called lithotrity or another termed lithontripsy.

Unless the stone be too large, my experience is that solvent treatment will prove effectual in nearly every case. The solvent treatment consists, of course, of such herbal agents as are chemically opposed to the nature of the calculus. By such a course of medication my success has been most gratifying.