2 Thomson, Atmospheric Pressure on A tiiuial Metabolism 



would produce a decrease in tlic percentage of CO^ 

 (decreased metabolism). 



Determinations made when the body was surrounded 

 by cold air showed greater metabolism than when it was 

 surrounded by warm or hot air, such comparisons having 

 been made in air at the ordinary temperatures as compared 

 with the air of a Turkish bath. Other observations, how- 

 ever, shewed that whilst the body remained in cold air the 

 metabolism was greatly increased whilst breathing warm 

 or hot air. 



Incidentally I may mention that the breathing of pure 

 dry oxygen did not produce greater metabolism than 

 the breathing of ordinary dry town's air, although the 

 oxygen was in such excess that a red hot tip on a splinter 

 of wood burst into flame when put into a jar filled with the 

 exhaled air, and finally that highly ozonised air produced 

 a decrease in the metabolism. 



In considering the effects of the altered conditions of 

 the atmosphere on animal metabolism not only must the 

 counteracting influences of pressure and humidity be 

 considered but also that of temperature and the con- 

 dition of the person breathing, because we found that the 

 metabolism was much increased for some time after taking 

 violent exercise. 



Finally the mode of breathing had to be carefully 

 taken into account, the percentage of CO. being increased 

 by retaining the inspired air longer than usual in the 

 lungs. 



The first experiments were made by breathing three 

 times through a glass tube |-inch diameter into an 8-ounce 

 bottle provided with an accurately-fitting well-vaselined 

 glass stopper, [)reviously expelling about a third of the 

 breath to eet rid of the residual air from the mouth and 



