My friend, Dr. Granville, like every other man of genius, has a hankering after a theory; but he was too shrewd not to see that this monstrous German hypothesis of “vitality” would be too large even for the swallow of John Bull. He has therefore substituted a much more rational and intelligible reason for the effects of thermal spas—namely, their _caloricity_, as differing materially from that of common water heated to the same degree of temperature. It is very easy to conceive that cauldrons that have been kept boiling in the bowels of the earth for thousands of years, will have diffused the caloric more uniformly and minutely through the waters, and dissolved more completely the mineral ingredients, than pots and kettles in the laboratory of the chemist. This, in all probability, is the solution of the mystery respecting the superior efficacy of thermal spas. The composition of the Kochbrunnen is as follows:—Forty-four grains of common salt—five of muriate of lime—one and a half of carbonate of lime, out of fifty-nine grains in the pint. The remaining nine grains are not worth enumerating, as the salt and lime are clearly the main ingredients. There are only seven cubic inches of carbonic acid gas in the pint. The temperature is little short of 160° of Fahrenheit. Let us begin with the baths. At a temperature of 86° to 90°, the bath generally occasions a slight sensation of chilliness, which goes off in a few minutes, and is succeeded by a feeling of comfort—serenity of mind—and ultimately a degree of weariness or lassitude, inclining the bather to lie quiet and repose himself. The volume of the body rather diminishes than expands, and the skin of the hands and feet are gently corrugated—the pulse becomes slower and softer—irritability is lessened—spasmodic feelings (if they existed,) disappear under the soothing influence of the waters on the nervous system and circulation—the functions of the intestinal tube are encreased, as are those of the skin, kidneys, and various glandular organs. At a temperature of 94° to 98°, the bather, at the moment of immersion, experiences an agreeable sense of warmth—the vital powers are exalted, and all the functions of the organs are put into a state of increased activity. The pulse expands and quickens, but is still soft—and all the secretions and excretions are augmented after leaving the bath.