Gases of the Blood 593 



Experiment CLIX. January 24. Large hunting dog. Left femoral. 

 75 cc. of blood taken; the analysis was lost by accident. 



74 cc. then taken; the animal, which had been tied down for a long 

 time, had been perfectly quiet (A) ; at the end of an hour, the ani- 

 mal excited struggled violently, howling loudly, for some minutes, 

 after which 76 cc. of blood were taken (B). 



Blood A contains per 100 volumes: O* 18.6; CO* 37.0. 



Blood B contains per 100 volumes: O* 19.4; CO 35.2. 



Experiment CLX. March 5. Small dog, whose laryngeal recurrents 

 were cut March 1, but in good shape. Femoral artery. 



The animal being very calm, 40 cc. of blood were drawn (A) ; 

 then the dog is made uneasy by placing a little ammonia under its 

 nose, and the same quantity of blood was drawn (B). 



Blood A contains per 100 volumes: O* 11.7; CO 33.6. 



Blood B contains per 100 volumes: O 12.4; CO* 32.7. 



The dog was then poisoned by curare; the excitation of a sciatic 

 nerve made the blood pressure rise 2 cm., to 4 cm., even after the 

 section of the two pneumogastrics. The peripheral end of these no 

 longer acting on the heart, the central end, when excited, increased 

 the blood pressure. After having cut transversely the right half of 

 the lumbar cord, an increase of pressure was obtained by excitation 

 of the right sciatic; the left gave a doubtful result. 



Here are two experiments that indicate that in most cases one 

 does not need to give much consideration to any modifications in 

 the behavior of the animal at different moments of the experiment. 

 The comparative analyses show that for oxygen the causes of error 

 hardly reach unity, and that for the carbonic acid they hardly 

 exceed two units. 



But in certain exceptional circumstances, the differences may 

 reach values that are much higher. That happens sometimes, for 

 example, when the trachea of an animal is opened and a cannula 

 is inserted. All physiologists have noticed that in these conditions 

 the animals are often seized by an extraordinary panting, which 

 usually ceases at the end of a few minutes. Now if blood is drawn 

 during this period, we find that its gaseous composition is very dif- 

 ferent from what it was before. 



I shall offer as examples the two following cases, the most re- 

 markable I have found. 



Experiment CLXI. December 20. Vigorous dog, weighing 16.5 

 kilos. 



At 3:55, I drew from the carotid 33 cc. of blood, which is quite 

 dark .... A. 



At 4 o'clock, I placed a tube in the trachea; the respirations 

 became extremely rapid for 5 minutes; then calm returned and shortly 

 after, a new acceleration, which ended at 4: 10, the very moment when 



