Gases of the Blood 657 



So the hypothesis is verified, and above 1 atmosphere, the 

 pressure adds to the blood only the oxygen dissolved, whose in- 

 creasing proportion follows Dalton's Law. 



If then we take 20 as average proportion of oxygen contained 

 in the blood at normal pressure, and if we assume, to make the 

 calculation easy, that there is one volume dissolved, we shall find 

 that at 6 atmospheres there will be 25 volumes; at 12 atmospheres, 

 31 volumes; at 18 atmospheres, 37 volumes. 



These last results are marked on the graph of Figure 46 by 

 points whose series naturally forms an absolutely straight line. 

 Now if we had drawn on the same scale the graph of Experiment 

 CCXIII and had then traced back the whole to its point of origin 

 (14.9) on the line marked 20, the four points of this graph would 

 be represented by the little crosses on the graph. We see how 

 close they are to the theoretical points. 



There has been added between 1 atmosphere and vacuum a 

 reduction of graph A of Figure 43, which completes the survey of 

 the capacity of blood for oxygen, from the lowest to the highest 

 pressures. 



The question arose whether for high pressures the temperature 

 would cause any important difference in the capacity of the blood 

 for oxygen. Since the experiments which I have just reported 

 were carried on at the temperature of the laboratory, I performed 

 another, shaking the blood in a bath kept at 40°. As the results 

 agreed with the preceding, I thought it unnecessary to gather more 

 data. 



Here is the experiment. 



Experiment CCXIV. January 15. 300 grams of arterial blood were 

 drawn from a large dog, and were defibrinated and filtered through 

 linen. 



I placed 130 grams in the apparatus of Figure 31; I compressed 

 the air to 22 atmospheres, and agitated the blood and the air for a 

 half hour, the apparatus being submerged in water at 40°. 



I lowered the pressure to 18 atmospheres, and 5 minutes after, 

 I removed 28 grams of blood .... A 



The pressure being lowered immediately to 12 atmospheres, I 

 agitated the blood again and removed 33 grams . . . . B 



A similar procedure gave me at 6 atmospheres 41 grams of blood. 

 . . . . C 



Finally, at normal pressure, I had left 20 grams of blood . . . . D 

 The analysis by the pump showed that: 



A (18 atmospheres) contains, per 100 volumes: O^ 35.7; N 19.2. 



B (12 atmospheres) contains, per 100 volumes: O 30.9; N 15.1. 



C (6 atmospheres) contains, per 100 volumes: O- 27.1; N 7.8. 



D (1 atmosphere) contains, per 100 volumes: O^ 23.0; N 1.3. 



