1893.] on the Interchange of the Respiratory Gases. 



Results of Experiments under Exercise. 

 B. F. Davis, in Winter, 1 2 hrs. after a Meal. 



49 



The figures obtained under the heading " O and C0 2 absorbed," 

 were, with the exception perhaps of the first, fairly close to each 

 other, with a mean of 103 c.c. By multiplying the factor 0'123 

 found in my experiment by the mean excess of C0 2 under exercise 

 over C0 2 in repose (the data in repose being obtained from other 

 experiments), and subtracting the result from the O and CO 3 found 

 as absorbed, as was done in the other case, the figure for carbonic 

 acid absorbed is 50, and for absorbed 53 ; the latter being very 

 near " 55," which is, for Mr. Davis, the mean volume of oxygen 

 absorbed after a meal in the state of repose. Therefore, again, in 

 the present case in the winter experiments, between 1 and 2 hrs. 

 after a full meal, by applying the factor 0'123, we find the same 

 volume of oxygen absorbed under exercise as when in a perfect 

 state of repose. In the experiments on Mr. Davis, the third stage 

 had been omitted, as the experiments were done before any attempt 

 to judge experimentally of the C0 2 absorbed in the blood had been 

 thought of. 



So far the results of these experiments must be considered as de- 

 pending to a great extent on the season of the year winter on 

 the time which has elapsed since food has been partaken of 

 1 2 hrs. and on the period during which exercise has been taken 

 a period not exceeding 18 or 19 mins. It stands to reason that after 

 exercise has lasted a certain time the blood cannot take up any more 

 C0 2 , and this time does not appear to exceed 19 or 20 mins. It was 

 found, experimentally, that after that period the volume of C0 2 

 accumulated in the blood varies greatly. 



The exercise was continued in other experiments for 33 mins., 

 42 mins., and 1J hrs., when the volume of C0 2 Adored up in the blood 

 was found to range from c.c. to 353 c.c. in the warm summer 

 weather the C0 2 formed under exercise appears to leave the blood 

 at the lungs more rapidly than in winter. So far I have not suc- 

 ceeded in finding any uniform volume absorbed during any given 

 time in spring and summer, although a number of experiments were 

 carefully made with that object in view. 



VOL. LIV. E 



