Gases of the Blood 607 



In my experiments, just one of the differences observed is ex- 

 plained by the state of the animal, in Experiment CLXXIV. Here 

 we were handling a small dog (4 k.) , from which five days before 

 I had drawn 110 cc. of arterial blood, that is, about half of the 

 amount the loss of which would have killed it immediately, and 

 which had remained sick and without appetite ever since. In the 

 first experiment, its blood had given 19.4 per cent of oxygen and 

 48.4 of carbonic acid; in the second, there was only 13.3 of oxygen 

 and 34.9 of carbonic acid: the two gases had therefore diminished 

 considerably. 



The variations of the carbonic acid are, as I said a while ago, 

 considerably more extensive than those of the oxygen, but are no 

 easier to explain: there is involved a collection of problems analo- 

 gous to those which we (MM. Mathieu and Urbain and I) have 

 already studied, and which would require very numerous experi- 

 ments. 



And now having come to the point which should interest us 

 especially, a glance at the figures in Columns 8 and 9 of Table X, 

 compared to the corresponding figures of Columns 3 and 4, show us 

 that in all cases, under diminished pressure, the oxygen and the 

 carbonic acid have diminished in the arterial blood. There was no 

 exception to this general rule. 



This is expressed very clearly in Figure 31 by the graphs com- 

 posed of dashes connecting the little circles o — o — o — . In this graph, 

 the quantities of gas are measured on the axis of the y's and the 

 pressures on that of the x's; the points on it have been determined 

 by the following procedure. 



I took the figures which express the averages and which are 

 placed at the bottom of Table X. I assumed that the initial value, 

 at normal pressure, of the oxygen (Col. 3) was always 20, and that 

 that of the carbonic acid (Col. 4) was always 40. Then the values 

 at different pressures (Cols. 8 and 9) were modified by operations 

 like the following: 



Average of the experiments from 1 to 4 — 

 Oa 19.3 (col. 3) : 20 = 16.9 (col. 8) : x = 17.5 

 CO2 37.7 (col. 4) : 40 = 33.2 (col. 9) : x = 35.2 



Similarly, at each pressure, I made the same calculation, not 

 for the averages, but for the extreme values of the modifications, 

 and obtained thus the points marked by the little isolated circles 

 which accompany the two curves representing the averages. 



The same data are expressed under a different form, perhaps 

 more simple, by Columns 12, 13, 14 and 15. Columns 12 and 13 



