(a) Simple Alkaline Waters (containing carbonate of soda as a main ingredient), are such as those of Vichy and Neuenahr, Salzbrunn, Mont Dore, Bilin, Gieshubel, Apollinaris, etc.

(b) Muriatic Soda Waters contain in addition sufficient chloride of sodium to correct the dyspepsia or debility sometimes induced by a pure soda water, and are those of Luhatschowitz, Ems, La Bourboule, etc. (v. pp. 158, 159).

These and the preceding waters are ordered in cases of acid gravel, gout, venous stasis, and abdominal obstruction, in scrofulous exudations, in diabetes, and in chronic catarrh of the respiratory, gastric, or genitourinary tract. In catarrh especially, waters containing chloride are to be preferred.

(c) Bitter Waters ("purging saline waters") containing sulphate of soda and magnesia as chief ingredients are such as Friedrichshall, Hunyadi Janos, Pullna, Seidlitz, Epsom, Beulah Spa, Purton, Cheltenham, Leamington, Scarborough (v. pp. 159-161).

One or two wineglassfuls of these waters (preferably taken warm) stimulate the gastro-intestinal mucous membrane, and produce a watery discharge from its glands. They are useful in habitual constipation, especially when this is connected with torpor or congestion of the liver; but if given too frequently, or in excessive dose, they are apt to bring on flatulence, dyspepsia, or intestinal catarrh in delicate subjects.

(d) Compound Soda Waters (containing sulphate of soda in effective doses) are Carlsbad, Marienbad, Franzensbad, Tarasp, etc. (v. pp. 161-163). These are ordered in gout, gravel, diabetes, and catarrh, like the simple soda waters, and also more especially in dyspepsia, corpulence, jaundice, gall-stones, and hyperaemic enlargement of the liver, and in haemorrhoids occurring in plethoric persons. These waters, if freely used, are markedly lowering in their action.

(c) Common-Salt Waters include those of Homburg, Kissengen, Baden-Baden, Wiesbaden, Reichenhall, Kreuznach, Harrogate (v. pp. 163, 168).

These waters are used, taken cold and in but moderate quantity, in dyspepsia and gastric catarrh; also in constipation and chronic intestinal catarrh; for early stages of abdominal plethora, and for haemorrhoids and venous stasis occurring in thin depressed subjects; also in bone disease and scrofulous exudations, inflammatory effusions, and glandular and even fibroid tumors.

Class 3 - Sulphur Waters, which contain alkaline sulphides or sulphuretted hydrogen, are found at Aix-la-Chapelle and Aix-les-Bains,

Weilbach, Bareges, Luchon, Cauterets, Harrogate, Llandrindrod, Moffat, Lisdoonvarna, etc. (v. pp. 168-172). They are used for chronic syphilitic and scrofulous disorders, bronchial catarrh and phthisis, chronic hepatic congestion, chronic rheumatism, and metallic poisoning, such as that from lead or mercury. The digestive powers are liable to be taxed by a course of these waters, and more or less anaemia is apt to follow. Good meat diet is desirable while sulphur is being taken.