The ancient Romans and Greeks, we are told, when covered with sweat and dust, used to plunge into rivers without receiving the smallest injury. Though they might escape danger from this imprudent conduct, yet it was certainly contrary to sound reason; many robust men have thrown away their lives by such an attempt. We would not, however, advise patients to go in the cold water when the body is chilled; as much exercise at least ought to be taken as may excite a gentle glow all over the body, but by no means so as to overheat it.
To young people, and particularly to children, cold bathing is of the utmost importance; it promotes their growth, increases their strength, and prevents a variety of diseases incident to childhood.
It is necessary here to caution young men against too frequent bathing, as many fatal consequences have resulted from the daily practice of plunging into rivers, and continuing there too long.
The most proper time of the day for using the cold bath is, no doubt, the morning, or at least before dinner, and the best mode, that of quick immersion. As cold bathing has a tendency to propel the blood to the head, it ought always to be a rule to wet that part as soon as possible. By due attention to this circumstance, there is reason to believe that violent head-aches, and other complaints which frequently proceed from cold bathing, might be often prevented.
The cold bath, when too long continued, not only occasions an excessive flux towards the head, but chills the blood, cramps the muscles, relaxes the nerves, and wholly defeats the intention of bathing; hence expert swimmers are often injured, and sometimes lose their lives. All the beneficial purposes of cold bathing are answered by one immersion at a time, and the patient ought to be rubbed dry the moment he comes out of the water, and should continue to take exercise some time after.
Doctor Franklin, who was almost always a practical man, says, "that the only obstacle to improvement in this necessary and life-preserving art, is fear; and it is only by overcoming this timidity, that you can expect to become a master of the following acquirements. It is very common for novices in the art of swimming, to make use of corks or bladders to assist in keeping the body above the water; some have utterly condemned the use of them. However, they may be of service for supporting the body while one is learning what is called the stroke, or that manner of drawing in and striking out the hands and feet that is necessary to produce progressive motion; but you will be no swimmer till you can place confidence in the power of the water to support you. I would therefore advise the acquiring that confidence in the first place, as I have known several who, by a little practice necessary for that purpose, have insensibly acquired the stroke, taught as if it were by nature. The practice I mean, is this—choosing a place where the water deepens gradually, walk coolly in it until it is up to your breast, then turn your face towards the shore and throw an egg into the water between you and the shore, it will sink to the bottom and will easily be seen there if the water is clear; it must lie in the water so deep that you cannot reach to take it up without diving for it. To encourage yourself to do this, reflect that your progress will be from deep to shallow water, and that at any time you may, by bringing your legs under you and standing on the bottom, raise your head far above the water; plunge under it with your eyes open, which must be kept open before going under, as you cannot open your eyelids from the weight of water above you, throw yourself towards the egg and endeavour by the action of your feet and hands against the water, to get forward till within reach of it. In this attempt you will find that the water buoys you up against your inclination, and that it is not so easy to sink as you imagine, and that you cannot, but by active force, get down to the egg. Thus you feel the power of water to support you, and learn to confide in that power, while your endeavours to overcome it and to reach the egg, teach you the manner of acting on the water with your feet and hands, which action is afterwards used in swimming to support your head higher above the water, or to go forward through it.
"I would the more earnestly press upon you the trial of this method, because, though I think I shall satisfy you that your body is lighter than water, and that you might float for a long time with your mouth free for breathing, if you would put yourself into a proper posture, and would be still and forbear struggling, yet till you have obtained this experimental confidence in the water, I cannot depend upon your having the necessary presence of mind to recollect the posture and the directions I gave you relating to it; the surprise may put all out of your mind.
"Though the legs, arms, and head of a human body, being solid parts, are specifically somewhat heavier than fresh water, yet the trunk, particularly the upper part, from its hollowness, is so much lighter than water, as that the whole of the body, taken altogether, is too light to sink wholly under water, but that some parts will remain above until the lungs become filled with water, which happens from drawing water to them instead of air, when a person in the fright attempts breathing while the mouth and nostrils are under water.
"The legs and arms are specifically lighter than salt water, and will be supported by it, so that a human body cannot sink in salt water, though the lungs were filled as above, but for the greater specific gravity of the head. Therefore, a person throwing himself on his back in salt water, and extending his arms, may easily lie so as to keep his mouth and nostrils free for breathing, and by a small motion of the hand may prevent turning if he should perceive any tendency to it.
"In fresh water, if a man throw himself on his back near the surface, he cannot continue in that situation but by proper action of his hands in the water; if he have no such action, the legs and lower part of the body will gradually sink till he comes into an upright position, in which he will continue suspended, the hollow of his breast keeping the head uppermost.