On Mineral Waters, 65 



and the labours of a master in the art, have been rarely adopted 

 as the basis of an artificial preparation. The fallacious notion, 

 too, that a knowledge of the effects of a mineral water was de- 

 ducible from the ingredients, as they are enumerated in our 

 tables of analysis, became another source of failure. Imitations 

 were considered satisfactory, if they but contained those few 

 substances that preponderate in the originals, and which are 

 known in themselves as possessed of medical power ; whilst 

 others, either existing in smaller proportions, or whose curative 

 virtues, under the form our tables of analysis gave to them, were 

 less striking, were either entirely omitted, or added in incorrect 

 proportions. This error was particularly frequent with regard 

 to the oxide of iron. I have already once had occasion to ob- 

 serve, that a mineral water is by no means to be regarded as a 

 mere solution of those salts enumerated in our tables of analysis, 

 co-existing without reciprocal decomposition. The earthy car- 

 bonates, for instance, which, as such, would be of little medical 

 value, exist in mineral waters in the form of sulphates, muriates, 

 and bi-carbonates, the efficacy of which cannot be disputed. 

 Silica, which in its state of solid aggregation, is indolent, exists 

 in the waters as a soluble silicate*. 



The carbonate of iron, however minute its proportion may 

 be, has no inconsiderable share in modifying the effect of mi- 

 neral waters. Repeated observations have proved that in the 

 artificial Carlsbad waters, for instance, if the small quantity of 

 iron be omitted, they become possessed of the debilitating ten- 

 dency which saline aperients generally acquire, when used for 

 too great a length of time |. 



• It is sufficiently known how little we are allowed to transfer our therapeutical 

 notions of an insoluble body, to the same when in a state of solution. I allude merely 

 to the different effects of metals and their insoluble sulphurets, compared with their 

 soluble salts. The different intensity of aggregation — even a minuter state of me- 

 chanical division — freq\iently implies a considerable change in the medical virtues. 

 Calomel, prepared via humidA, or via sicca ; sulphur, sublimated or precipitated ; 

 oxide of iron, before or after ignition ; duid mercury, or those preparations wherein 

 it is minutely subdivided, &c. &€., furnish proofs. of this statement. The action of 

 many of our antidotes, by their entering into combinations, relatively insoluble, must 

 be referred to the same principle. 



t The salts of strontia, barytes, lithia, together with the fluates and phosphates 

 which some mineral waters yield, occur in proportions too trifling to admit of any 

 stress being laid on their medical effects. How far this remark applies to the more 

 prevalent manganese, which proves, from the late experiments of Professor Gmelin, 

 powerfully to affect the biliary secretions, we may not be too forward in presuming. 

 Be this as it may, it rests incumbent on chemists who profess to imitate a natural 

 spring, to omit no one ingredient; however inconsiderable it may appear. 



JAN.— MARCH, 1828. F 



