Soda salts are very useful in several forms of indigestion, but the dose and mode of administration vary somewhat according to the conditions present. In cases of atonic dyspepsia connected with deficient secretion of gastric juice, the bicarbonate in small doses of 5 to 10 gr. should be given, and shortly before a meal, on the principle already alluded to, viz., that an alkali causes increase of an acid secretion, for though on first contact it neutralizes the acid it meets with, additional acid is very quickly poured out so as to leave an excess. The alkali may, in some cases, be very suitably combined with an aromatic, as ill

"Gregory's powder," with ginger only, or with a bitter-like tincture of orange or infusion of gentian. On the other hand, in cases of acid dyspepsia, with thickly coated or red shining tongue, sour eructations, heartburn, and flatulence, larger doses of the bicarbonate (15 to 20 gr.) should be given an hour or more after a meal, according to the time at which the symptoms come on; in this case, also, the remedy may be well combined with an aromatic or stimulant, as ammonia or peppermint. Soda is especially useful for the dyspepsia of those who live in towns, eating and drinking freely, and taking little exercise. If the urine be scanty and irritating, nitre may be given at the same time, and according to Dr. Budd, an occasional blue pill. A dry skin and very furred tongue are other indications for soda, while for those who live in the country, take more vegetable food, and perspire freely, acids usually agree better (Medical Times, i., 1854). If larger closes of soda be continued too long, or taken at the wrong time, "it becomes a contest between the stomach and the doctor."

The familiar use of salt is of no small importance in stimulating appetite and digestion, and advantage is sometimes gained by varying the kind used: thus, Maldon salt is in crisp flakes, Lymington salt in deliquescent cubes, etc. (Medical Times, i., 1864). The principal ingredient in Vichy water is the bicarbonate of soda, but it contains minor or minute quantities of sulphate, phosphate, arseniate, borate, and chlorine: this saline water may be very useful in simple slow digestion, with constipation and loss of appetite, and when gastralgia is not a prominent symptom (H. Weber: Medical Times, ii., 1861). Dr. Symonds states that "duodenal dyspepsia," with its attendant "bilious headache," may often be obviated for a long period by the daily taking of a tumblerful of "salt and water" before breakfast (Medical Times, i., 1858). An effervescent soda carbonate, or sulphate, is often efficacious in such headaches.