OXYGEN GAS FOR ATHLETES 259 



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 



