640 Experiments 



gen. Quite evidently, the oxygen consumption by the tissues 

 could not have remained at the same value, which we have seen 

 to be above 9; now the analysis of the venous blood shows that it 

 dropped to 6.6, that is, that there still remains in the venous blood 

 2.2 volumes of oxygen, which the tissues cannot easily extract. 

 From this, there result for the animal evident metabolic disturb- 

 ances, a lowering of temperature, a general depression of the 

 muscles, particularly the heart, which adds still more to the dis- 

 tressing effect, lessening the oxygen consumption by lessening the 

 circulatory activity. 



The increasing difficulty of the dissociation of the oxy-hemo- 

 globin of the venous blood when its proportion of oxygen is les- 

 sened considerably seems to be the cause of the distress of the ani- 

 mal, which can no longer extract from its blood the quantity of 

 oxygen necessary for its metabolic equilibrium in a given tem- 

 perature. Now, the proportional quantity of oxygen consumed by 

 animals varies greatly from one individual to another, as, for ex- 

 ample, is shown by Experiment CXC, in which it is 9.2, compared 

 to Experiment CXCII, in which it is 3.3. Furthermore, the absolute 

 quantity of oxygen contained in a given volume of blood varies 

 decidedly also, as we have learned from the numerous analyses 

 already reported. Finally, the quantity of the blood itself likewise 

 appears very variable. It is not at all surprising then that the be- 

 havior of different individuals of the same species and even more 

 of representatives of different species should be very variable under 

 the effect of the same decompression, one being much affected while 

 the other experiences almost no effect. One can easily grasp this 

 idea by assuming two animals in which two of these three condi- 

 tions are identical and the third very different; it is useless to con- 

 tinue with this reasoning because we perceive a series of combina- 

 tions whose effect makes the problem very complex and makes it 

 impossible to predict the outcome with certainty. 



We shall refer again to these facts in the third part of this book 

 when we come to the explanation of the symptoms known by the 

 names of balloon sickness and mountain sickness. 



