Notwithstanding my qualms, Dr. Kœstler insisted on my taking one, and making myself acquainted with his darling Schlammbads from personal experience; and I must say, when quietly seated in the mire, the sensations were by no means disagreeable. In other hot mineral baths I almost invariably experienced an oppression and anxiety at the chest; but here, I know not why, the breathing was quite natural, and not at all hurried. The black mess was extremely acid, violently and instantaneously reddening litmus paper; and it exhaled a peculiar odour which I can compare to nothing but to blacking. Its taste was styptic and saline—styptic evidently from some salt of iron, and more saline than the water of any other mineral bath. This is no more than would be expected when the quantity of salt it contains is considered. I am informed by Dr. Kœstler that every bath requires 250lbs. of schlamm, in which are contained 33lbs. of salts. And this statement I should imagine to be tolerably correct, for I find that 120 grs. of this mud yield 15.5 grains of matter soluble in water. The solution is light brown, very acid, and contains the following substances: 1. A volatile acid, which was separated by distillation at temp. 230 circ. and which had many of the leading characters of acetic acid, and on which the peculiar odour of the bath depends.—2. Some fixed extractive matter in combination with iron.—3. A large quantity of the persulphate of iron; and 4. some sulphate of soda. In examining this specimen, I was mostly struck with the very large quantity of iron, and the comparative small quantity of other saline matter. For a wonder it contained no _chloride_. There is a salt kept by the chemists at Franzensbad, purporting to be the salt contained in the mud. Had they said—made from the mud, they would have been correct. It is perfectly neutral and efflorescent, and is nothing else but sulphate of soda, with just sufficient persulphate of iron left unremoved, to tinge its solution. The fact is—it is prepared by neutralising the acid solution of the mud by _carb. soda_, and thus precipitating the iron, and retaining the salt of Glauber in solution—one or two crystallisations furnish it tolerably pure. The opinion that it contained the phosphate of soda and phosphate of iron, is unfounded. In many respects, the mud-bath is unique in its action on the human body. From the quantity of saline matter it holds in solution, it acts as a powerful stimulus to the skin, exciting the capillaries to renewed exertions; hence its great use in gouty and rheumatic paralysis. The chalky and fibrinous depositions which form this disease are absorbed under its influence; and so effectual is it, that Dr. Kœstler, the oracle of Franzensbad, will prophecy the recovery of a patient from this disheartening complaint, after the far-famed hot springs of Teplitz have been tried in vain.