Pulmonary Gases in the Respiration of Man. 225 



It will be seen that the oxygen absorbed per minute when carbonic 

 acid was breathed greatly exceeded the oxygen absorbed when pure 

 :air was inspired. The figures given in the table for O absorbed 

 under normal conditions, are taken, with one exception, from experi- 

 ments made at the same sitting as those in which C0 2 was breathed, 

 and therefore compare with them. The excessive volume of oxygen 

 absorbed when air mixed with C0 2 was inhaled must have been owing 

 to the fact that a portion of the oxygen consumed, which under usual 

 circumstances would have been given out as carbonic acid, remained 

 in the blood, obviously as carbonic acid, because of the impeded 

 diffusion in the lungs on account of the C0 2 contained in the air 

 breathed. The actual amount of carbonic acid being thus retained 

 in the blood can be calculated, with what I think a near degree of 

 approximation, by subtracting the oxygen which would have been 

 absorbed in the respiration of pure air from the oxygen actually found 

 to have been absorbed under the influence of the C0 2 inspired. 



These figures, varying from 44 c.c. to 133 c.c., are entered in the 

 last column of the table, and show how large a volume of CO 2 may be 

 retained in the blood when air contaminated with C0 2 is used for 

 respiration. This carbonic acid goes on accumulating in the body inter- 

 fering with the normal phenomena of oxidation. It is very difficult 

 to consider this effect otherwise than poisonous ; although under cir- 

 cumstances which admit of the introduction of C0 2 in the blood 

 through another channel than respiration, the gas appears innocuous. 

 Cl. Bernard has shown this to be the case by the injection of C0 2 into 

 the circulation of animals, when the gas found its way out of the body 

 through the lungs without producing any morbid action. 



Description of a New Form of Eudiometer. 



A. Receiver containing hydrogen gas. 



B. Eudiometer. 



b. Three-way stopcock. 

 . Flask holding water. 

 D. Cylinder containing the gas for analysis. 



