{46} In the milder cases ether and chloroform may be of value given by the mouth, while in excessively severe ones anæsthetics by inhalation may be called for, and their use continued for hours. This course also is not without its inconveniences. The writer has seen a case where a somewhat prolonged maniacal attack, with delusions lasting several days, came on after the long-continued use of chloroform to relieve the pain incident to the passage of a multitude of small uric-acid calculi. The use of diluents has been suggested as hastening the passage, but there is no reason to doubt that the pressure upon the calculus is always sufficient to move it forward as rapidly as its shape and size will permit. The relaxation of the spasmodically contracted ureter is of much more importance than an excessive vis-a-tergo applied to the calculus. The treatment of the incipient calculus in the kidney or of the condition which gives rise to it must naturally vary according to its chemical constitution, which can only be certainly determined after its discharge, but as to which an approximate opinion can be formed from a knowledge of the tendencies and diseases of the patient and from an examination of the urine. The use of a largely-diluted solution of citrate of lithia or of acetate, citrate, or tartrate of potassium will probably prevent the deposition of uric-acid sand, and might even dissolve a small calculus, although the proofs of this having actually been done are not conclusive. If the urine be largely diluted the risk of the formation of a calculus of another kind--_i.e._ phosphatic--is not great. Simple water would be of great value in many cases, both as dissolving uric acid and as promoting the metamorphosis of tissue, upon some abnormality of which the accumulation of uric acid is supposed to depend. The benzoate of lithia, by the destructive action which Garrod has shown benzoic acid or its derivative hippuric acid to have upon uric acid and the solvent action of the lithia, may be of value. The phosphatic deposit, on the other hand, although beneficially influenced by a sufficient supply of water, is not so amenable to chemical influence as the other form, because it is much easier to render the urine alkaline than acid when any irritation of the urinary passages is present. The vegetable acids, however, pass into the urine, and may render it acid if in sufficient quantity. Benzoic acid becomes hippuric acid, and can be used to make the urine more acid, as it causes very little gastric irritation even in considerable doses. Boric acid also passes into the urine, and acidifies as well as disinfects it, and might perhaps be used to promote the solution of a phosphatic stone, though the writer is unaware of any instance in which this has actually been done. It does much toward diminishing suppuration in the urinary passages, upon which phosphatic urine largely depends.