Action of Carbonic Acid 909 



Placed on the floor, the animal totters and seems drunk; temper- 

 ature 39°; but it has no convulsive movements. It has wholly recovered 

 after 15 or 20 minutes. 



Blood A (insensibility) contained ._ O a 23.7; CO, 98.4 

 Blood B (sensitivity restored) contained CX 20.8; C0 2 31.7 



The air of the bag, at the end of the experiment, contained only 

 52.2% of CO, and 38.5% of oxygen. 



Experiment DCXIX. December 28. Dog. 



Respiratory rate 48, pulse 80; the carotid pressure varies from 15 

 cm. to 19 cm.; rectal temperature 39°. I take 25 cc. of arterial blood . . A 



At 3:30, caused to breathe through a muzzle into a bag containing 

 air with 40.9% of carbonic acid, with 45.6% of oxygen. 



The inspirations become deeper; but there is no struggling. At 

 3:33, pinching the sciatic nerve gives no reaction as to sensitivity; the 

 arterial pressure is from 18 cm. to 21 cm., there are 44 respirations, 

 pulse 152. I take 25 cc. of arterial blood . . . . B 



3:35. Muzzle removed. Almost immediately convulsive struggling 

 occurs. Sensitivity returns at 3:40, and I take 25 cc. more of carotid 

 blood . . . . C 



The pressure is then from 14 cm. to 16 cm., and the temperature 

 is 39\ No delayed symptom. 



Blood A (free air) contained 21.8 of oxygen and 44.6 of CO. 



Blood B (insensibility complete) contained 23.2 of oxygen and 78.6 of 



CO, 

 Blood C (sensitivity restored) contained 22.1 of oxygen and 51.5 of CO, 



The preceding experiments show first that, in the cases when 

 they ended in death, it occurred when the respiratory medium 

 contained 35.4% of CO, (Experiment DCXIV), or 39% (Experi- 

 ment DCXI) , or 45.7% (Experiment DCXV) . These numbers dif- 

 fer from each other considerably, as is evident. 



On the other hand, some animals survived when the air which 

 they were breathing already contained 34.8% of C0 2 (Experiment 

 DCX), 37.3% (Experiment DCVI). and even 38% (Experiment 

 DCXIII) . 



Without dwelling for the moment upon these peculiar varia- 

 tions, let us consider what happens to the carbonic acid contained 

 in the blood. 



In the fatal cases, the proportion of CCX contained in 100 vol- 

 umes of arterial blood rose to 106.7 (Experiment DCXIV), 114.2 

 (Experiment DCXV) and 116.6 (Experiment DCXI); in the last 

 case, the venous blood contained 120.4 of CO,. 



On the contrary, in the experiments when death did not occur 

 in spite of the large proportion of carbonic acid in the air, there 

 was in the arterial blood only 82.8 of CO, (Experiment DCXIII), 



