The principal disorders attributed to cold are owing to its irregular application to the body overheated, or to a partial stream of cold air on one particular organ. From hence arise catarrhs, with all their attendant symptoms, and their accustomed danger; from hence fevers, rheumatisms, diarrhoea, and all the variety of epidemics, with their attendant evils, date their origin. Even the most destructive miasmata often rest innocuous in the body, unless excited to action by cold; and when we hinted that all catarrhs may originate from miasmata, we admitted that cold was an exciting cause. In this enumeration we have omitted two diseases attributed to cold: the chaps on the lips and skin, from the contraction of cold air; and the fragility of the bones, the fragile vitreum of Gaubius, supposed to be equally the effect of condensation. The former are scarcely diseases; and there is much reason to conclude, that the deep seated bones are little affected by the inclemency of the air. The internal parts preserve their usual heat in air of every temperature, without increase or diminution, as we have already shown; and if fractures are more common in cold weather, it must be recollected that our steps are then more unsteady, the ground harder, and irregularly uneven.

It has been contended, that cold is, in its primary action, a stimulant; but the idea arises from the refinements of system, rather than observation. From the first effects of cold, what has been styled reaction so suddenly follows, as to mislead the incurious or the prejudiced attendant. The dispute will, however, at last, become verbal: for it is in no case contended that its stimulus will be injurious; and geuerally admitted, that with little, often imperceptible stimulus, it may be quickly rendered a powerful sedative.

If we look to cold as a remedy, we shall find a more cheering prospect. In our observations on cold bathing, we have distinguished it in its immediate, its continued, and repeated action. When we speak of cold in this place, we treat chiefly of its immediate and its continued action; for cold applications are principally useful in these ways. We were almost led to confine our remarks to the latter; but there are some facts which will not admit wholly of this explanation.

Cold is highly useful in fevers of almost every kind, though it will often admit only of the slight application of cold air; and rheumatic fevers seem to be the only exception. The heat forms the true indication for its use; since, in the early stage of intermittents, or in the exhausted state of protracted typhi, it is less admissible. When there is considerable heat, and no fixed organic affection of the internal parts, cold is often a very salutary remedy. We have, indeed, some instances, where, in a protracted cold fit, the application of cold has hastened the reaction; but the practice will be dangerous, unless the patient is strong and active. The effect of cold in the hot fit of fevers is to lessen the heat, and hasten the perspiration. This discharge is checked when the heat is considerable, and seldom takes place when it is much above 100°. Dr. Alexander places the perspirable heat too high, viz. at 108°.

Synocha is well adapted to this remedy; but it seldom occurs without the combination of internal inflammation, except when owing to worms, or sordes in the abdomen. In each case, cold must be employed with some caution and discrimination. Yet cool air and cool drinks may be allowed. Let us take this opportunity of making the distinction. By cold, when we speak of drinks, we mean, in general, from 51° to 40°; by cool, from 48° to 60°. The coolness of air is more relative; and, in general, means from 10° to 15° below the mean heat of the chamber, which should never exceed, if possible, 62°. It will be obvious, that these numbers arc-not to be taken with minute precision, but only as a general standard.

In typhus, the use of cold is a subject of greater nicety. Cool air and cool drinks are always proper, except when the patient sinks from faintness. Yet De Haen, as we have already observed, used it in a low epidemic fever, at Breslaw, with some appearance of success; Dr. Gregory has sponged the body with cold water or vinegar; and the practitioners of America have employed it even more boldly in this, and its kindred disease, the yellow fever. The exhibition of calomel, at the same time, does not seem to deter them; and, indeed, till some effect on the gums appears, no benefit is derived from the medicine. Should it produce this peculiar symptom, its worst consequence, little disadvantage would probably arise. In some instances, very cold water has been employed as a clyster; and ice, in a bladder, applied to the stomach, or other parts, suffering under acute pain. From ourselves we can say little; we have, in a few instances, employed it certainly without injury; we can scarcely say with any striking advantage. Where the heat is great, it may be most freely used: when inconsiderable, sponging is the most ad-viseablc application of cold, and vinegar mixed with water may have its advantages. The different parts of the body should be sponged also in succession.

Phlegmasiae. Ophthalmia has been constantly benefited by cold applications; and the fact is so generally understood, that we need not enlarge on it. Even ether, which produces a considerable degree of cold by evaporation, has been employed. Cynanche, we are told by Dr. Rogers, is relieved in the northern climates by-rubbing ice externally on the throat. A practice not very dissimilar is recommended in some parts of England, holding a piece of nitre or sal prunella in the mouth. Some caution is necessary, that this remedy be not employed in the malignant angina. In phrenitis, the utility of cold applications is sufficiently known and well established: but in the other internal inflammation it is a suspicious remedy. From its utility in hernia we may be led to employ it in enteritis. In this disease, cold water has been dashed against the legs and thighs with advantage; but it will be recollected, that, in hernia, enteritis, and cynanche, we approach so near the part affected, that the cold is almost an external application; and, though we have mentioned among the effects of cold a costive state, we then spoke of its continued application in a cold climate. In nephritis we are told, by Mercurialis, that cold is useful; and, as we can so nearly reach the bladder, either by the perinaeum or above the pubes, we suspect it may be useful also in cystitis.