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are used in some disordered conditions of the digestive organs, especiallywhen connected with hepatic derangement, in dropsical complaints, inuterine affections, and in various other cases, which will be more fullynoticed when treating of carbonic acid. When the acidulous waterscontain the protocarbonate of iron, their effects and uses are analogous tothose of the ferruginous springs already noticed. The acidulo-alkalinewaters are useful in the lithic acid diathesis, in gout and rheumatism, &c.The acidulous or carbonated waters are objectionable, on account of theirstimulant effects, in febrile, inflammatory, and plethoric subjects.
Class 4. Saline mineral waters (Aqua minerales salines ).—These waters owe their medicinal activity to their saline ingredients; foralthough they usually contain carbonic acid, and sometimes oxide of ironor hydrosulphuric acid, yet these substances are found in such smallquantities as to contribute very slightly only to the medicinal operationsof the water.
Saline mineral waters may be conveniently divided into five orders,founded on the nature of the predominating ingredient.
Order 1. Purging saline waters .—-The leading active ingredient ofthe waters of this order is either the sulphate of soda or the sulphate ofmagnesia; but the chlorides of calcium and magnesium, which areusually present, contribute to their medicinal efficacy. Those springs,in which the sulphate of magnesia predominates, are called bitter —asthose of Epsom, Scarborough, and Seidlitz. The springs of Cheltenham ,Leamington, and Spital, contain sulphate of soda. In full doses thewaters of this order are mild cathartics. In small and repeated dosesthey act as refrigerants and alteratives. They are useful in diseasedliver, dropsical complaints, habitual constipation, haemorrhoids, determi-nation of blood to the head, &c.
Order 2. Saline or brine waters .—The characteristic ingredient ofthese waters is chloride of sodium. Iodine or bromine has been recog-nized in some of them, and doubtless contributes somewhat to the medi-cinal effects. The most important brine springs of England are those ofMiddlewich and Nantwich, in Cheshire ; Shirleywich, in Staffordshire ,and Droitwich, in Worcestershire. The springs of Ashby-de-la-Zouch ,in Leicestershire , contain, besides chloride of sodium, a considerablequantity of chloride of calcium. Taken in large quantities, saline orbrine waters are emetic and purgative. In small but continued dosesthey act as alteratives, and are supposed to stimulate the absorbent sys-tem. They have been principally celebrated in glandular enlargements,especially those which are of a scrofulous nature.
Order 8. Calcareous waters .—Those saline mineral springs whosepredominating constituent is either sulphate or carbonate of lime, orboth, are denominated calcareous waters. The Bath, Bristol, and Buxtonthermal waters are of this kind. When taken internally, their usualeffects are stimulant (both to the circulation and the urinary and cuta-neous secretions), alterative, and constipating; and are referrible, in part,to the temperature of the water, in part to the saline constituents. Em-ployed as baths they are probably not much superior to common waterheated to the proper temperature ; but they have been much celebratedin the cure of rheumatism, chronic skin diseases, &c. Bath water isgenerally employed both as a bath and as an internal medicine in variouschronic diseases admitting of, or requiring, the use of a gentle but con-