Pulmonary Gases in the Respiration of Man. 221 



The mean ratio of C0 2 produced to O absorbed is, therefore, very 

 different according to temperatures ; it is much lower in relatively 

 cold than in warmer temperatures ; hence the interesting fact that 

 the absorption into the blood of that proportion of oxygen consumed 

 which is not transformed into carbonic acid is not concerned in the 

 production of heat towards resisting external cold. This is clearly 

 the case, as the colder the atmosphere the less the proportion of 

 oxygen consumed as absorbed in opposition to the proportion con- 

 sumed towards the production of carbonic acid, which is markedly 

 increased. A similar effect of temperature is met with in the experi- 

 ments reported in my former paper. Out of six experiments made 

 on myself under the influence of food, two were carried out 2 hrs. 

 25 mins. and 1 hr. and 40 mins. respectively after a meal, when 

 the laboratory in winter was much below its usual temperature, 

 tjie readings being 10'4 C. and 12 C. ; on these occasions the 

 oxygen absorbed per minute was 27 c.c. and 24'8 c.c. respectively, 

 and the mean ratio between the CO 2 produced and O absorbed was 

 25 '9 

 OQQ = 0*114 ; while when the laboratory was comfortably warm, at 



a mean temperature of 16 '8 C., the mean volume of oxygen absorbed 

 was 32*4 c.c., and the ratio oTo~ = 0*152. Hence, again, the ratios 



were lower in low than in high temperatures, which means that 

 in my case in low temperatures less oxygen is absorbed, relatively 

 to the carbonic acid produced, than in high temperatures. The expe- 

 riments while fasting reported in my former paper were all made when 

 the laboratory was comfortably warm, and cannot be utilised towards 

 showing the influence of temperature. 



With Mr. Darnell Smith, who kindly submitted to experiment, the 

 results are as follows : 



