In all those cases where death is occasioned by drinking cold water, it will be found that the body, heated and fatigued by exertion, was rapidly losing heat by profuse perspiration, the person having generally at the time ceased his exertions. If the exertion had been continued, or at any rate the heat kept at its previous standard, no danger would have resulted. It was in this way, that Alexander lost more of his army than had ever been slain in his most bloody battle, when they, thirsty, weary, and perspiring with their long march across the desert, rushed wildy into the cold waters of the River Oxus.

Following out the principle we have just laid down we are taught a vast number of useful facts.

The traveler need apprehend but little danger from wet feet, or a wet skin, provided he keep up active exercise, changes his clothes as soon as that exercise ceases, and avoids future applications of cold. It is very common with bathers, after having become heated by a walk or violent exercise, to pause for a while before plunging into the water, and, as they term it, "cool off," after which they rush in and remain some time. This, you will perceive, is not only unwise, but highly dangerous. Far better plunge in at once, paddle about, remain but a few moments, then come out and dress. And so the young lady, fatigued and heated with dancing, had far better get into her carriage, ride home and jump into bed than to stand in this state for a little while and partially "cool off" in the entrance hall before starting. And the gentleman similarly situated, will feel much better the next day from having put on his over coat and walked briskly home.

Recollect that heat, preternaturally accumulated by exercise, is dissipated by profuse perspiration, and speedily lost, when to this is added rest after fatigue, and that then the application of cold is liable to be followed by unpleasant results.

A very constant effect of continued heat is, to stimulate the organic functions of the body. We have evidence of this in the luxuriant vegetation of warm climates in comparison with the stunted growth of colder regions. As you approach nearer and nearer the poles, not only vegetables, but animals become stunted. The inhabitants of warm climates are much larger than those of frigid regions. Notwithstanding there may not be much difference in point of size between the inhabitants of the torrid and temperate zone, yet the former reach maturity much sooner than the latter, and it is not uncommon to find among them females married and the mothers of children at the age of twelve or fourteen. Continued heat also produces a depressing influence on the animal functions, causing lassitude and want of energy. Those nations who have most signalized themselves in the world's history, and left the largest record on its pages, have been those, not in equatorial regions, but in the more northern and cold climates. From causes already explained, the prominent affections in warm climates are those of a dysenteric or bilious character.

The effects produced by cold are directly the reverse to those of heat. It acts, when long continued, as a sedative on the animal functions. There is a shrinking: of the external parts, and a paleness or deadness of the skin. One of the first effects of cold on the system, is extreme drowsiness, followed by a stupor or sleep, during which the poor victim glides without a pang into the arms of death. This sense of drowsiness is often so great, that notwithstanding the person is conscious, that to sleep is to die, he cannot rouse himself.

There are times, however, when cold not too intense, produces an entirely different effect, acting as a tonic, stimulating, refreshing and invigorating the mind and body. It then becomes a most important curative agent. I have only to instance the well known effect of cold bathing, where it is followed by reaction.

A momentary sensation of cold, however intense, is seldom injurious, but long-continued shivering will be very likely to end in disease. The effect of cold is more injurious when applied by currents of air. This is particularly the case when the current strikes only one portion of the body. Better expose the whole body to the same temperature, than have a current playing on one portion. Cold is far more prejudicial to health when accompanied with moisture. Hence a damp cold, foggy atmosphere is much more likely to produce disease, than a clear and dryer one of the same temperature. Wet and damp clothes prolong the sensation of cold, and extract more heat from the body than is generated within, and unless exercise or stimulants are made use of, deranges the circulation and creates internal disturbance.

We have seen that the amount of animal heat remains nearly the same in all temperatures and in all climates. That the air of colder regions is more condensed and with the same number of respirations we inhale a much greater amount of oxygen than in the rarefied atmosphere of warmer climates, that it is absolutely essential to life that the rapidity with which animal heat is generated should vary in the different temperatures of the earth.

There is nothing which renders the system more liable to the injurious effects of cold than want of proper nourishment. Dissipation also prostrates the system and in a measure paralyzes the power of nature. In cold weather the food of course should be nourishing, the clothing warm, and exercise when in the open air, active. In our northern climates it is generally best to wear flannel next the skin throughout the year, thinner in summer of course than in winter. Being a bad conductor of heat it prevents that of the body from being quickly dissipated, and therefore in a measure guards against the frequent changes of temperature so common in our climate.

It also absorbs the perspiration, and by its constant friction in movement, gently stimulates the vessels and nerves of the skin. I fully appreciate and insist on the necessity of comfortable warmth to insure health, and yet I have no sympathy with the growing effeminacy of the present day. To see the young, who should be full of life and activity, and possess the strongest and most vigorous powers of generating heat, muffled up in cloaks, padded coats and furs, in this climate, forcibly reminds one that they may be better acquainted with the reeking fumes of the bar-room, the halls of revelry and the haunts of dissipation, or the heated air of the drawing-room, than the healthy, manly, and active duties of life. It certainly bespeaks a ridiculous effeminacy, and one from which they themselves will be the greatest sufferers. Pure and healthy recreation, manly and vigorous exercise in the open air, conquering cold by increased physical exertion, nourishing food, and moderately warm clothing, are far better than piles of furs or hosts of mufflers. In addition to this, prepare the system before going out by washing from head to foot in cold water.