1911.] 



The Physiological Influence of Ozone. 



413 



variations in the metabolism in successive periods of time. These were due 

 to want of complete rest on the part of the subject. (See Table IV.) 



Our last series of experiments were carried out with the subject recumbent 

 on a couch and prepared for the test by a preliminary period of rest. Even 

 then, the opening and shutting of the windows (to vary the condition of 

 ozonisation of the air) must have somewhat influenced our results by altering 

 the cooling effect of the air on the body. These tests were carried out in 

 warm summer weather, and in the final experiment the windows were kept 

 shut all the time and the room ventilated by opening the doors leading into 

 other and larger laboratories. In this experiment we obtained results which 

 we regard as the most conclusive of all. 



The metabolism varies with the degree of complete rest of the subject. If 

 he moves slightly more or less, e.g., in reading, talking, this will affect the 

 result, and thus we cannot expect figures more concordant than those we 

 have obtained. Looking at the figures in columns IV and VI, we cannot 

 find any conclusive evidence that ozone altered the respiratory metabolism. 

 Note particularly the final experiment (No. 7), in which the windows were 

 shut and the conditions even all through. 



The ozone was given in a concentration that made the air smell quite 

 strongly, and in some cases it was pushed even to an unpleasant degree. 

 Taking these figures together with those obtained on mice, we must conclude 

 that we have failed to obtain certain evidence that inhalation of ozone in 

 weak concentration stimulates the respiratory metabolism, i.e., the output of 

 of C0 2 and use of 2 . On the other hand, our experiments conclusively 

 show that any considerable concentration of ozone depresses the respiratory 

 metabolism. 



We think that the beneficial results obtained by the use of pure ozone in 

 ventilation must be reached by the effect of ozone on the nervous system — 

 by its stimulating the mucous membrane, neutralising smells, and relieving 

 the depressing uniformity of close air. Our experiments show that no harm 

 results to man from breathing air ozonised till the air smells quite strongly 

 of ozone, for periods of half to one hour. 



Perhaps the most interesting observation made in the research is this: 

 when the respiratory tract is irritated by ozone, the animal becomes motion- 

 less, sits hunched up with its fur erect, thus showing the signs of depression. 

 The ozone lessens the respiratory exchange, reduces it even to one-seventh, 

 at a time when the lung shows no changes visible to the naked eye ; the 

 animal adjusts its behaviour to this condition, and keeps very still and 

 quiet. Its body temperature at the same time falls. The damage to the 

 lung cannot be serious, since this depressant effect is quite evanescent. 



2 h 2 



