594 Experiments 



33 cc. more of blood was being drawn, which was evidently not so 

 dark . . . . B 



Blood A contains per 100 volumes: O 15.1; CO 40.8. 



Blood B contains per 100 volumes: 20.3; CO 24.0. 



Experiment CLXII. January 24. Bulldog. 



At 2:30, I extracted 32 cc. of blood from the carotid, the animal 

 breathing through the natural channels ... A 



I opened the trachea to place a tube in it; the respirations became 

 extraordinarily hasty; at the end of 5 to 6 minutes of this rhythm, I 

 took 33 cc. of blood, considerably redder . . . . B 



Blood A contains per 100 volumes: O, 16.0; CO, 41.5. 



Blood B contains per 100 volumes: O 23.4; CO 15.2. 



But, I repeat, this is an extreme; nothing quite comparable ap- 

 peared in animals breathing through natural channels. A great 

 number of experiments permit me to state that the circumstances 

 depending upon the animal's behavior, although not negligible, are 

 not such as to forbid the drawing of conclusions. Of course, I could 

 not always prevent interference from them, but when it was very 

 manifest, I abandoned the experiment. 



Finally, without dwelling on the differences which may appear 

 in the blood of a dog, depending on whether the animal is fasting 

 or digesting such and such kinds of food, I shall say that all of my 

 dogs had eaten food with very little meat about eight o'clock in 

 the morning; the experiments were generally performed from two 

 to six o'clock. 



We see that definitely the sources of error contained in our 

 analyses, which have both chemical and physiological causes, are 

 about one unit for oxygen and three or four units for carbonic 

 acid. I maintain that in practice one cannot attempt to obtain 

 greater accuracy than this without mistaking a systematic error 

 for the truth. 



Subchapter II 



GASES OF THE BLOOD UNDER PRESSURES 

 OF LESS THAN ONE ATMOSPHERE 



1. Experimental Set-up. 



Extraction of blood from the vessels of an animal subjected to 

 the influence of diminished pressure was not an easy problem. 



The apparatus at my disposal, which I used in my researches in 

 diminished pressure, is composed of two vast cylindrical chambers 

 (Fig. 27) which can be isolated from each other by a communicat- 

 ing door. These chambers are 2 meters high and 1 meter in 



