Respiration is the act of breathing. It is divided into two distinct parts—inspiration and expiration. Inspiration is the drawing in of air through the nostrils or mouth, and past the glottis into the trachea. Expiration is the driving out of the air. Inspiration is immediately followed by expiration, then there is a slight pause before the next inspiration. The respiratory act is repeated from thirteen to fifteen times a minute when an adult is breathing calmly. The act of inspiration is performed by the contraction of the diaphragm towards the abdomen, thereby increasing the depth of the thorax from above down wards, and the air immediately rushes in to distend the lungs and prevent the formation of a vacuum between the inner and outer pleura. As soon as the diaphragm ceases to contract the air is expelled, as the thoracic cavity becomes smaller. In addition to the action of the diaphragm, the inter-costal muscles contract, the ribs are raised, and the sternum or breast-bone forced outwards, thus increasing the depth of the thorax from the sternum to the spine. As soon as they relax the ribs come back to their normal position, and in this they are also probably aided by other muscles.
It is a remarkable circumstance,' says Professor Huxley, • that the mechanism of respiration is somewhat difkrent in the two sexes. In men, the diaphragm takes the larger share in the process, the upper ribs moving comparatively little ; in women the reverse is the case, the respiratory act being more largely the result of the movement of the limbs.' There is a certain amount of stationary air in the lungs, and into this is diffused the oxygen from the fresh air taken in, whilst the carbonic acid which it has taken from the blood through •the walls of the capillaries is driven out. This process of exchange is ever proceeding, the whole of it being regulated from a nervous centre in the medulla oblongata, which is a eon-, tinuation of the spinal cord at the base of the brain. Death from drowning is the result of asphyxia, the stoppage of a supply of pure air to the lungs. The oxygen gradually diminishes while the quantity of carbonic acid increases, and at length the air in the lungs becomes too impure to effect an exchange with the blood. Then the blood passing into the heart becomes venous, and at length the heart sends out to all parts of the body venous instead of arterial blood. Immediately a dull sickening pain, and one which under-water swimmers dread, because insensibility rapidly ensues, becomes apparent at the back of the neck. This arises from the affection of the re spiratory centre in the medulla. In a very short space of time the brain is poisoned, the face becomes black through the veins being gorged with blood, and the heart ultimately ceases to beat.
The most important point in all resuscitation work is first of all, if possible, to send for a medical man. But even then no time must be lost in proceeding to restore breathing. The restoration of natural breathing must be the first effort ; once that is accomplished, then the promotion of circulation and warmth may be attempted. When using the Silvester method, if no sign of life can be observed, nor the heart's action heard, the patient should be laid flat on the back, the dress loosened, and a roll of clothing or a pillow placed under the shoulder blades, the arms during this operation being handled carefully.
The mouth and nostrils should then be cleared, and the tongue drawn forward. An elastic band or a strip of handkerchief, passed over the tongue and under the chin, may be used for this purpose. The best method of clearing the throat will be found in the 'resuscitation drill of the Life-saving Society.
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As soon as the throat is cleared and the tongue drawn: forward—and too much stress cannot . be given to the fact that it is of vital importance to see that the tongue does not fall back into the mouth—the operator should immediately proceed to imitate the movements of breathing. The arms of the patient should be grasped just belovi the elbow, and then drawn steadily upward full length above the head, and down beyond it until they are in line with the rest of the body. This raises the ribs and expands the chest, thereby allowing fresh' air to enter. The arms should be kept in this position for about two seconds, and then carried back again and pressed firmly against the sides and front of the chest for another two seconds, so as to . produce an expiration. These move Ments should be repeated carefully for•about fifteen times a minute, and persevered with until natural: respiration begins, or a medical man arrives and takes charge of the case. Friction should not be resorted to until a spontaneous effort is made to respire. In the absence of .a medical man, the treatment should be maintained for hours, as the Royal Humane Society are aware of successful cases even after five hours' perseverance.. All'utinecessary'crOwding round a patient should be prevented, and' care should be taken to avoid any rough usage, especially the bending or twisting of the limbs. Death is generally cated :by the entire cessation of breathing and the heart's: action ; the eyelids are half-closed, the. pupils dilated ; the tongue approaches to the under edge of the lips, and these, as well as the nostrils, are covered with a frothy mucus. Coldnesi. and pallor of the surface increase.
If natural, breathing be restored, the operator should attend. to the mouth, nose, and throat, and see that warmth is properly" encouraged by placing hot-water bottles or hot bricks on the soles of the feet, the pit of the stomach, under the armpits, &c., whilst the assistants should resort to friction over the surface of the body, so as to assist the circulation. All rubbing should be along the body, in the direction of the heart, so as to assist the propulsion of the blood through the veins. The friction on the legs should all be upward, not first upward and then downward, and along the arms towards the body. If dry blankets or clothing are available, the patient should be wrapped in them, and the friction continued under the blankets or over the dry clothing. When the power of swallowing has returned, a teaspoonful of warm water, very small quantities of warra brandy and water, wine, beef-tea, or coffee, should be given, the patient placed in bed, and a dis position to sleep encouraged. If there be difficulty in breath ing, a mustard plaister or hot linseed-meal poultice should be applied to the chest and below the shoulders. A doctor should always be summoned, even if the preliminary work detailed has been successfully accomplished in his absence, as complications arising from the entrance of water into the lungs sometimes ensue.
The Silvester method is taught by the Life-saving Society, as are also the other two systems named, by means of a drill. It has been found, most effective to use a drill for the purposes of general instruction, and as each point is carefully explained, the pupils at the end of the course of lessons generally pass the final examinations, both theoretical and prac tical, in a highly creditable manner. In this, again, Mr. Wilson was to the fore, the original drill—upon which the following, now used by the society, was based—being formulated by him.