530 Experiments 



pressure quite comparable to those which the preceding calcula- 

 tions indicated. It is a matter of care and patience. 



If now we examine Column 11 of Table I, we find numbers 

 representing the result of the addition of the carbonic acid pro- 

 duced and the oxygen remaining at the moment of death. They 

 are represented by the line C0 2 + 2 in Figure 17. We see that 

 these different numbers vary between 17.8 and 20.5: the general 

 average is 18.9. And so we find at all diminutions of pressure the 

 fact observed by earlier authors, which caused them to make such 

 strange hypotheses on the nature of asphyxia in closed vessels, that 

 is, the diminution of the elasticity of the air, or, in other words, 

 the disappearance of a certain quantity of oxygen which is not 

 recovered in the carbonic acid given off. Furthermore, — and this 

 is very evident on the graph — this amount keeps increasing when 

 the pressure diminishes; above one half atmosphere, it is on the 

 average 18.7, and below, it is 19.2. So, at very low pressures, there 

 is given off a greater proportion of carbonic acid in comparison to 

 that of the oxygen absorbed. In studying the gases of the blood 

 under diminished pressure, we shall easily understand this 

 phenomenon. 



That is not all: a careful inspection of Column 11 shows us 

 another interesting fact. If we group on one side all the cases in 

 which the number indicated in Column 10 is between 3 and 3.5, and 

 on the other all those in which this number is above 3.5, we shall 

 find that for the first series the average is 18.6, while for the second 

 it rises to 19.5. That means that the greater the exhaustion of 

 oxygen, the greater has been the quantity of this gas not recovered 

 in the carbonic acid exhaled. Hence we can draw the conclusion 

 that in asphyxia in closed vessels, whatever the pressure may be, 

 towards the end of the animal's life, the oxygen, which it continues 

 to absorb in very small quantities, remains in the tissues under 

 some form or other, without giving rise to carbonic acid. 



This conclusion is corroborated also by the examination of 

 Column 12 of the table, containing for each experiment the ratio 

 between the carbonic acid produced and the oxygen consumed. 

 We see that these numbers are in a general way proportionately 

 smaller as the pressures become lower. In the first eleven experi- 

 ments (above a half-atmosphere) the average is 0.85, and for the 

 others only 0.80. We conclude then that at very low pressures the 

 proportion of oxygen that is absorbed without producing carbonic 

 acid is greater than at more moderate pressures. 



I tried to ascertain whether some relation existed between the 



