What, then, was the principle evolved in this experiment, which gave immediate relief? Did it consist in the half ounce of muriate of soda alone, or in the four scruples of sesquicarbonate of soda alone, or in the ten pints of water alone, or in the whole combined, or more especially in the high temperature to which the solution was raised? It is a well-established fact that, in order to raise the temperature of cold water to blood heat and above, a large amount of free caloric must necessarily be absorbed, and exist mechanically in the fluid; and, in this condition, the solution was introduced into the veins, and there evolved its vast amount of free caloric, which immediately permeated every organ of the system, arresting disease, raising the temperature of the body, and restoring its normal functions. Of this there can be little doubt. For free caloric is one of the most prompt, effective and diffusive stimulants known, and was evidently in this case the remedial agent which produced the result. True, it may be said the effect was transitory, and passed off as soon as the caloric became eliminated. This, however, cannot alter the nature, character, or influence of the principle on which it was produced. It is usually admitted that a remedy that has power to control disease, will, by its continued action and influence, restore the normal condition of the system permanently, or at least aid Nature to repair her own work. By this we would not be understood as advising a repetition of the experiment under consideration, even under the most urgent circumstances; far otherwise would be our advice. We are arguing for the purpose of evolving and establishing a general principle of practice. The great question, then, is, Did the principle evolved fulfill the indications required? and if so, is it available and consistent with the pathology and the peculiar phenomena, or symptoms of the disease? To settle this point, we need only turn to the law and the testimony, the very highest authority on the subject. The doctrine now universally accepted and prevailing regarding its pathology is, that a poison, virulent, and subtle, and unknown, has been absorbed and infects the blood, so that, after a longer or shorter time, a primary disease of this vital fluid is produced, by which the vital energy is impaired, and all other morbific changes induced. The term "Algide," first used by the French Pathologists, very accurately describes one of the most remarkable and constant symptoms, viz., the diminution of animal heat. On this depend the altered condition of the blood, the depression of the nervous power, the impaired functions of the respiratory and all the vital organs which are essentially involved by the disease. The icy coldness of the surface, the breath, the extremities and general loss of temperature, all show the character of the disease and the wants of the system.