Majuhester AltiHflirs, Vol. Ivii. (1913), No. 13. 



XIII, On the Influence of Atmospheric Pressure, 

 Temperature and Humidity on Animal Metabolism. 



By William Thomson, F.R.S.E., F.I.C, F.C.S. 



[Rtiid Mar, h 21 si, igii. Kacived for pitbliidUoii, April 32nd, jgrj.) 



In a previous paper' I pointed out that in making 

 determinations of the percentages of carbon dioxide 

 (CO2) contained in the air exhaled from the knigs of 

 different persons, that on certain days the percentages of 

 C0._, were all, or nearly all, relatively high whilst on other 

 days they were all, or nearly all, relatively low. 



That a number of persons should be thus similarly 

 affected gave presumptive evidence that the cause lay, not 

 in the individuals, but in the conditions of the atmosphere. 



I therefore commenced a series of carbon dioxide 

 (CO.J determinations in the exhaled air from a number 

 of persons, making at the same time observations of the 

 barometer, the hygrometer and the thermometer. 



I had previously determined that the percentage of 

 CO2 in the exhaled breath was greater when the air 

 inhaled had been previously dried by passing over strong 

 sulphuric acid, and I assumed therefore that it would be 

 found that the metabolism would be greater when breath- 

 ing dry than when breathing damp air. 



Determinations made showed greater percentages of 

 CO2 in the exhaled air at high elevations than in the valley, 

 and higher in the valley than at the bottom of a deej) coal 

 pit, and this led to the assumption that a fall of the 

 barometer would produce an increase in the percentage of 

 CO2 (increased metabolism) whilst a rise in the barometer 



' Read before the Seventh Inteinalional Congress of Applied Clicniislry, 

 1909, London. Seclion V'lII. A., Volume Hygiene and Medicinal 

 Chemistry, p. 154. 



