Since the preceding chapter on ozone was written I have learned that this peculiar triple-condensed variety of oxygen (it is called by chemists “O3” whereas ordinary oxygen is “O2”) is now being most successfully applied to the purification of the water-supply of several large cities. A notable case is that of the great winter resort, Nice. Ozone gas is one of the most effective destroyers of organic impurity known; it destroys both bacterial germs and the putrescible impurities of water completely, and is itself converted in the process into harmless health-giving oxygen, whilst the water is rendered absolutely free of all germs. It is readily manufactured by treating oxygen with the electric discharge, and is produced at a cost which renders its use in water-purification an economical and financially satisfactory method. The use of ozone gas as a medicinal application to cavities in the living body in which disease-producing bacteria are lodged is making progress. It has to be administered with great care by a medical expert, and though there has been delay and opposition on account of the novelty of the treatment, there are signs that ozone will become established as a valuable therapeutic agent. It is a singular fact that so little has been done of late by scientific observers either as to the presence of ozone in the atmosphere or as to the action of ozone on the healthy animal body when present in minute quantity in the air taken into the lungs. The general opinion appears to be that it is either altogether absent from the atmosphere or present only in quantity so minute as to be negligible from the point of view of the physiologist except in very high mountain regions, and there the exact quantity remains undetermined. The only experiments in the last ten years on the subject of its action on animals are some which led the inquirers to the conclusion that constant exposure (in a closed chamber) to an atmosphere containing 4 per cent. of ozone caused death after five or six days by an inflammation of the lungs. Clearly it is desirable that further investigation on this subject by competent authorities should be made, and the effect of smaller quantities of ozone in the air respired, whether continuously or at intervals, should be ascertained.
The action of ordinary oxygen gas is a separate matter. The atmosphere which we breathe consists of one part by volume of this gas and of four parts of nitrogen gas. It is the oxygen which is necessary to us and to all animals, and the nitrogen is merely an inert diluting accompaniment of the essential oxygen gas. It is, of course, easy to increase or to diminish the proportion of oxygen in the air breathed accordingly as one introduces additional pure oxygen or, on the other hand, diluting nitrogen into a collapsible bag or sac from which one continuously draws breath. Such a bag can be connected by a tube to a helmet or mask enveloping the head. The expired air is discharged by a specially provided passage. It used to be thought that it was dangerous to breathe pure undiluted oxygen, although the proportion of oxygen to nitrogen in the air taken into the lungs might be increased to as much as a half without injury, and, indeed, with great benefit in some serious conditions of collapse. Dr. Leonard Hill, F.R.S., of the London Hospital Medical College, has, however, recently shown that oxygen gas, of 97 per cent. purity, may be breathed continuously for as much as two hours without any ill-effects or sense of inconvenience. Contrary to what has been stated, it is neither exciting nor unpleasant. He has made the experiment on himself and on some of his assistants, and in doing so has made use of such an apparatus as that above-mentioned—so as to ensure the in-take of undiluted oxygen.
Dr. Hill and Mr. Martin Flack have further found that the exhaustion and labouring of the heart which is brought on by such special exertion as that involved in running a hundred yards race or a quarter-mile race, is almost completely avoided if the runner “fills his lungs” with oxygen gas before starting. The runner takes the oxygen gas into the lungs for some two or three minutes before starting to race; of course, the lungs are not thus actually “filled” with oxygen, but a much larger proportion of that gas is lodged in them than when ordinary air is breathed, and a full supply is thus afforded to the blood. The “distress” caused by violent athletic efforts appears to be entirely due to the using up of the available oxygen by the unusual activity of the muscles. The heart itself suffers most, the breathing becomes laboured, and there is a sense of suffocation, due simply to the urgent demand by the blood, heart and muscles for more oxygen. If, therefore, we ensure that there is an extra supply of pure oxygen in the lungs before the unusual effort is made, we avert these distressing symptoms: the unusual quantity of oxygen needed is ready for use. Dr. Hill himself and young men who have tried the plan of inspiration of oxygen before a foot-race, declare that they cannot believe that they are really running hard, even when surpassing their usual performance. They come in at the end of the quarter-mile, having beaten their record; and with no sense of having made a special effort; they feel fresh and ready to start again after more oxygen and a short rest. Moreover, the after-effect on the muscles is stated to be such that “stiffness” and what is called “grogginess” (due in ordinary circumstances to the retention of lactic acid in the muscle) do not supervene.
Swimming and diving, as one would expect, are greatly affected by the preliminary oxygen inhalation; the length of time during which submersion can be endured without discomfort is doubled, and the great effort of fast swimming rendered less rapidly exhausting. Cycling uphill at a rapid pace becomes, according to Dr. Hill’s own frequent experience, possible after oxygen inhalation when in ordinary conditions it was impossible. Hockey players and boxers he has found notably benefited by oxygen given both in the intervals of and after the exercise. It is, of course, to be expected that a wider practical application should be made of this simple method of increasing our power of sustaining muscular effort, and of enduring submersion. Dr. Hill suggests that the divers of the Mediterranean, who, without any apparatus, plunge into the shallow sea and remain below long enough to find, cut, and bring to the surface the valuable sponges of commerce, might use the method of preliminary inhalation of pure oxygen gas. He has also tried the method with a young racehorse, but owing to the fact that the course run was only a mile, and the animal perfectly fit and strong, he tells me that no advantage was found to result from the inhalation. With an older cart-horse somewhat tired by a day’s work—he obtained the most satisfactory results, the animal becoming obviously recuperated and working without distress.
The question has been raised as to whether the administration of oxygen gas to a man or to a horse when about to run a race should be considered as “doping.” It may perhaps be objected to by sportsmen, as involving the provision of special apparatus which all competitors would not be equally able to secure. But it is not “doping,” since that applies to the use of a drug, which, whilst exciting to violent effort, produces an injurious after-effect. Oxygen is not in this category; to take an extra quantity of oxygen into the lungs before starting on a race is no more unnatural or risky than to take an extra drink of water into the stomach or to swallow meat extract and such special preparations before or during a race. It would be interesting to see whether a runner in the Marathon race would (as Dr. Hill would expect) be greatly assisted if his trainer carried with him a supply of pure oxygen, and from time to time refreshed him with it. Football players might also be given oxygen at half-time; an oxygenated team would, one surmises, beat its uninspired competitors. A Fife team is reported to have done so. On the roads favoured by cyclists one may expect hereafter to find at the bottom of a long ascent hawkers of “breaths of oxygen” provided with gas-bags and calling out “Buy the lady a breff, sir!” It is, perhaps, worth noting that the relief afforded by oxygen-breathing is no less definite when the gas is taken immediately after a race or sustained effort than when used as a preliminary. The excess of choke-gas or carbonic acid formed during great muscular effort is not the principal cause of the distress experienced. That gas is thrown off by increased expiration. It is the using up of the oxygen and the insufficiency of the supply in the atmospheric air inspired that causes, under these circumstances, giddiness, exhaustion, and often collapse.
The difficulty in breathing and the prostration experienced by many people in mountain-climbing is largely due, not merely to the muscular effort of climbing, but to the fact that the rarefied atmosphere at heights of 8000 ft. to 15,000 ft. and more gives into the lungs in every inspiration but a fraction of the oxygen which is inspired at low levels, and moreover, owing to the low pressure, much less is held in the blood. Even when conveyed by mule, cog-rail, or balloon to these heights—and, therefore, without muscular exertion, sensitive people suffer severely from temporary “oxygen-starvation.” They as well as the laborious mountaineer could be saved from all such inconvenience by the use of a skilfully-constructed “traveller’s flask” of oxygen gas.
The observations and experiments as to the possible use of pure oxygen by athletes suggest that we might all benefit by occasional if not frequent use of such an atmosphere. Indeed, there are some individuals—amongst others a well-known and distinguished actor—who before making some special effort, or even when feeling tired and unequal to their daily work, inhale under medical supervision a certain quantity of oxygen gas. It would certainly seem that since country air, sea air, and mountain air are useful and refreshing, an artificial supply of extra oxygen might be inhaled in London, either in one’s own house or in establishments provided for the purpose, with definite benefit to health, especially if the inhalation were combined with exercise.
The experiments made by Dr. Hill have come about in connection with work undertaken for the purpose of improving the diving and life-saving apparatus named after its inventor, Fleuss. This invention consists essentially in a water-tight helmet and jacket connected with a cylinder of compressed oxygen gas which is carried by the diver. The advantage of such an arrangement is that the diver is free from pumping apparatus and can go where an ordinary diver could not. Mr. Fleuss was able, by diving with this apparatus, to prevent an immense loss of property by arresting the flooding of the Severn tunnel which was imminent during its construction. A difficulty in regard to the Fleuss apparatus has been that oxygen gas is a poison, causing inflammation of the lungs and convulsions when under a pressure of from two to three atmospheres—that is to say, at from 30 ft. to 60 ft. depth in water. The pressure exercised by the air of the atmosphere at sea-level is equal to that exercised by a column of water 30 ft. high, and hence at 30 ft. depth in the sea the oxygen gas would be under the pressure both of the atmosphere itself and of water to the same amount—which is expressed by saying that it is under two atmospheres’ pressure, or twice the atmosphere’s pressure. The pressure of the atmosphere is, in plain figures, 15 lb. on every square inch of surface. Of course, the oxygen is compressed far beyond this point in the cylinders in which it is carried. In using it, it is allowed to escape by opening a valve leading into an elastic sac, and is then and there subject to the pressure depending on the depth of water to which the diver has descended. It is found to be dangerous for a diver with this apparatus to descend to a depth of more than 30 ft. having pure oxygen in his apparatus, because the oxygen is then compressed under a pressure of two atmospheres. Accordingly, Dr. Haldane, of Oxford, has proposed that the oxygen should be diluted with atmospheric air, so as to give a mixture of equal volumes of oxygen and nitrogen. With this mixture the diver can safely descend to a depth of 60 ft. The apparatus is provided with a partition containing caustic soda, which absorbs the carbonic gas thrown out of the lungs in expiration. With such an apparatus a diver can safely remain under water at a depth of 60 ft., and walk about and explore for as long as two hours. A most important application of this self-contained diving apparatus is found in its use in the exploration of mines, where smoke or gaseous products resulting from an explosion render it impossible for rescue parties to penetrate without its use. It has been the means of saving many lives in such circumstances. A form of this apparatus is made in which the oxygen is supplied, not by a cylinder of compressed gas, but by granules of a chemical compound called pneumatogen, a peroxide of sodium and potassium, which when breathed into absorbs carbonic acid from the air expired by the lungs, and gives off pure oxygen. Submarine ships are now being provided with a dress or outfit of this description for each member of the crew, so that in the case of the entrance of water into the submarine, every man can put on his “oxygen helmet,” and one by one, when the ship is full of water, they can pass out by the conning tower and float to the surface. The perfected diving dress, with self-contained diluted oxygen supply and other improvements, has been constructed by Siebe, Gorman, and Co., and was exhibited by Dr. Leonard Hill at a soiree of the Royal Society.