Action of Carbonic Acid 



919 



With 40 of CO. in the air, there was 95 of it in the blood. Dif- 

 ference 13. 



With 45 of CO, in the air, there was 114 of it in the blood. Dif- 

 ference 19. 



We see that increases in the arterial blood which do not differ 

 much correspond to equal increases in the respirable air; this re- 

 sult conforms to the laws of physics. But we should not attribute 

 to it too great an exactness, because important changes in the 



Fig. 77 — Death by carbonic acid; relation of the respiration and the circu- 

 lation to the carbonic acid content of the blood. (Exp. DCXV.) 



respiratory rhythm may modify considerably the quantity of car- 

 bonic acid contained in the arterial blood. 



Let us now drop these chemical considerations and discuss the 

 changes which occurred in the various functions. 



The number of heartbeats decreases progressively; the tables 

 summarizing Experiments DCXIV and DCXV show that clearly, 

 and line P of Figure 76 still more clearly, at least for Experiment 

 DCXV. If we draw up graphs with the results of this experiment, 

 taking for abscissae, not the time elapsed since the beginning of 



