The ‘Silvester method,’ invented by Dr Henry Silvester, is now acknowledged to be far more effective than Dr Hall’s method, and is adopted by the Royal Humane Society for the restoration of the apparently drowned. It consists in laying the patient on the back, slightly raising the head and shoulders, drawing the tongue forwards, and keeping it so by passing an elastic band over it and under the chin. The arms are then grasped just above the elbows, and drawn gently upwards until they meet above the head (this is for the purpose of drawing air into the lungs), keeping the arms in that position for two seconds. The patient’s arms are then turned down, and pressed gently and firmly for two seconds against the sides of the chest (this is for the purpose of pressing the air out of the lungs).
Artificial breathing is thus carried on. These efforts are repeated fifteen times in a minute, until a spontaneous effort to respire is perceived. During the employment of these means the nostrils are excited with snuff or smelling salts, or the throat is tickled with a feather. After natural breathing has been restored, warmth and circulation are induced by wrapping the body in hot blankets, applying bottles or bladders of hot water, heated bricks, &c., to the pit of the stomach, the armpits, between the thighs, and to the soles of the feet, and by rubbing the limbs upwards firmly and energetically.
In the ‘Landw. Versuchs Stat.’ (xviii, 81-169)[138] Rudolph Pott has recorded a series of interesting experiments instituted with the object of determining the comparative quantities of carbonic acid excreted by respiration and perspiration in different species of animals in equal intervals of time; together with some experiments on the excretion of carbonic acid by the same animals under different physiological conditions.
[138] ‘Journ. Chem. Soc.,’ 1876, vol. i, p. 721.
The author states that in his researches he used an air tight box, with glass sides, in which the animal is placed, and through which the air can be drawn at any rate required by means of an aspirator.
The air before entering the glass chamber passes over caustic potash and through baryta water; after leaving the chamber it passes through three flasks containing known quantities of baryta water.
In the first part of this paper the author estimates the amount of carbonic acid excreted by different animals during the space of six hours, and under otherwise similar circumstances. The following are the most important conclusions he arrives at:—
1. The greatest quantity of carbonic acid in proportion to their weight is given off by birds. Mammals are the next in order. Insects exhale less than either of these.
2. Worms, amphibia, fishes, and snails form another group which excrete much less carbonic acid. Of these worms exhale the most and snails the least.
3. Those animals of the second group, which live in water, give off the greatest part of their carbonic acid to the air, and only a much smaller portion to the surrounding water.