1881.] On the Influence of Altitude upon Respiration. 



421 



finally, the combination of the carbonic acid was completely effected 

 by moving about the cylinder, so as to make the alkaline solution run 

 up and down the inside of the glass for a period of ten minutes, this 

 lapse of time having been ascertained experimentally to be amply 

 sufficient. The milky fluid was withdrawn into a small bottle, 

 carefully labelled, holding about 100 cub. centims., the bottle was well 

 corked, and the cork secured with paraffin wax so as to prevent 

 effectually the admission of air. I analysed the contents of the 

 bottle on my return to Y voire. 



The experiments, numbering eighty, have been disposed in a tabular 

 form ; they are distributed as follows : — 



Fourteen were made on myself at Yvoire, and ten on M. David ; 

 eight on myself at Courmayeur before ascending the Col du Greant, 

 and eight on returning to Courmayeur, nine on M. David at Cour- 

 mayeur before ascending the mountain, and seven on his return to 

 Courmayeur. Twelve on myself at the summit of the Col du Geant, 

 and also twelve on M. David at the same station. 



I shall beg to commence by inquiring into the influence of food and 

 temperature upon our breathing. 



Influence of Food. — In my former investigations, the direct influence 

 of meals as increasing the amount of carbonic acid expired was, as 

 a rule, well marked. The limited range of time that elapsed after a 

 meal previous to an experiment, and the small number of experiments 

 at each station in the present inquiry, preclude any but comparatively 

 wide results being arrived at as to the direct influence food exerted 

 on the formation of carbonic acid. Dr. Edward Smith* concludes 

 that the greatest quantity of carbonic acid is expired from one and a 

 half to two and a half hours after a meal ; in the present experiments, 

 the ingestion of food showed a direct influence in my case towards 

 increasing the amount of carbonic acid expired, although we cannot 

 find any definite tendency of the kind with M, David. At Yvoire, I 

 expired the smallest quantity of carbonic acid between breakfast and 

 luncheon, when the mean of four experiments undertaken during that 

 period yielded 0*479 grm. The carbonic acid rose under the influence 

 of a full luncheon, and attained a maximum of 0*572 grm. 1 h. 45 m. 

 after that meal in the first series of experiments, and of 0*638 grm. 

 3 h. 2 m. in the second series. At Courmayeur, before ascending the 

 Col, my minimum carbonic acid (0*449) was expired 4 h. 35 m. after 

 breakfast, and the maximum (0*554) 2 h. 40 m. after luncheon. On 

 our return to that station, my minimum (0*434 grm.) is expired at 

 the latest experiment after breakfast, and my maximum (0*561 grm.) 

 3 h. 35 m. after luncheon. So far the results agree tolerably, for 

 such a small number of experiments, with the influence food is usually 

 found to exert on the formation and expiration of carbonic acid. 

 * " Phil. Trans.," 1859. 



