The air in different localities differs most obviously and importantly in four particulars, namely, as to whether it is still or windy, whether it is cool or hot relatively to the local surface, whether it is heavy or rarefied, whether it is dry or saturated with moisture. It is also an important fact that the atmosphere consists of layers and currents differing in these qualities, and that the higher layers can be reached by ascending to high-lying lands. At the same time it seems that in a flat country the ascent of a comparatively low hill brings you into a layer or “stratum” of air differing more from that of the plain or valley than would be the case were you to ascend to the same height in a mountainous region. The seaside and the mountain may owe the beneficial character of their air to some of the varying qualities noted above. Chemical differences may or may not be important, and seem hardly to have been as yet brought within the range of accurate knowledge. Ozone may be more or less present, so may perfumes and volatile oils, such as are given off by pine trees, and there may be more or less minute quantities of carbonic acid and of sulphurous acid, and still minuter quantities of the newly-discovered gases—argon and helium—which, for all we know, may have some effect on the human body. There seems to be a great field open for accurate investigations in regard to the action upon human health of all these varying conditions of the air. In the meantime, we proceed by guesswork, and are influenced by tradition and beliefs which are based on a sort of experience, but are of a very vague and unsatisfactory description.
The case is much the same with regard to the natural waters of celebrated resorts. So far as their chemical composition is known, they can be manufactured and applied for drinking or bathing anywhere. But minute quantities of certain gases and other elements may be present in these natural waters and have escaped until now the observation of the chemist, and it is possible, though not demonstrated, that these rare chemical constituents may have some action on those who drink or bathe in the water. Ever since the time of the Romans natural mineral waters have been sought, and the springs which discharge them have been frequented, not because their chemical composition was known, but because experience seemed to show that they produced a beneficial result. It can hardly be doubted that the baths and springs frequented at the present day are not so much themselves the cause of the benefit to the cure-seekers as are the change of scene and diet, and the repose and regular life willingly accepted by those who travel so far to reach these springs.
With regard to ozone, there remains something more to be said, namely, in regard to its application, in a far less diluted form than is possible when it is taken into the lungs, to the destruction of putrefying organic matter and putrefactive and disease-producing bacteria. It is now some five or six years since air containing a high percentage of ozone—produced by the action of the electric discharge—was used for the purification of the water-supply of large towns. It is a fact that river water into which such ozone containing air is pumped becomes pure in the highest degree, in consequence of the destruction by the ozone’s oxydising action, both of the bacterial germs always present in vast numbers in river water and of the organic matter on which the bacteria depend. This application of ozone is in use in several large towns for the purification of drinking-water, for which purpose it has very great advantages. It has also been successfully used by Dr. Allen, the director of the Plymouth Marine Laboratory, for keeping the water of the marine aquarium there in a state of purity and well charged with oxygen gas. A similar use has been made of oxygen containing a considerable percentage of ozone by enterprising surgeons for the cleansing of ulcer and abscess. It is clear that such a gas may present mechanical advantages over any liquid application.
Ozone is not, apparently, in favour or fashion with the general body of medical practitioners at the present day, but possibly further examination and determination of its physiological properties may lead to its receiving more attention in medicine. Already the peroxide of hydrogen—which is more or less correctly described as “ozonised water,” and is used (under the name “Auricomous hair-wash”) to change dark hair by its oxydising action to a golden tint—is used by surgeons for washing out purulent wounds and abscess. Those who use the gas itself only go a step further. Some day we may see a more general use of ozone; on the other hand, it remains to be seen by direct and accurate experiment whether its properties are as valuable to man as we may hope they will prove to be.
[XXVII]
OXYGEN GAS FOR ATHLETES AND OTHERS
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.