610 Experiments 



46 cm., the quantity of carbonic acid had remained almost the 

 same as at normal pressure. These results are expressed in another 

 form in Columns 6 and 11, indicating the proportion of carbonic acid 

 and oxygen under different pressures. We see that at normal 

 pressure this proportion varied from 1.5 to 2.7, with an average of 

 1.9, whereas at low pressures it varied from 1.5 to 3.8, with an 

 average of 2.3. In almost all cases, the figure of Column 11 is 

 higher than the corresponding figure in Column 6, whether the 

 latter is high or low: the exceptions (Exp. CLXXV, CLXX, 

 CLXVII, CLXXIV) are cases in which the blood at normal pressure 

 contained small quantities of carbonic acid, varying from 29.1 to 

 35 cc. 



These data can be expressed in a more precise manner by the 

 following formula: 



The combination of oxygen with the hemoglobin is likely to 

 be partially destroyed, to be dissociated, at low pressures; this 

 dissociation becomes evident at a decrease of 20 cm. (pressure of 

 56 cm.). It increases as the decompression goes lower. At inter- 

 vals of 10 cm., we find the averages: from 56 to 46 cm., a loss of 

 7.5 per cent; from 46 to 36 cm., a loss of 21.9 per cent; from 36 to 

 26 cm., a loss of 7.7 per cent. The greatest loss then comes at 

 about a half atmosphere. 



The graph Ox of Figure 32 shows at the first glance the course of 

 this gradual loss of oxygen; on the horizontal axis are counted the 

 pressures, and on the vertical axis the percentages of the gases 

 which have disappeared (Cols. 14 and 15 of Table X) . 



As to the carbonic acid, it behaves in about the same way; only 

 its diminution is always less than that of the oxygen; this is 

 easily seen on the graph C0 2 . 



The graph shows again that the decrease in gases does not 

 follow Dalton's Law (which would be represented by a line bisect- 

 ing the angle of the coordinates). The carbonic acid is farthest 

 from it. Yet I must say that the deviation is not very great for 

 either gas. 



That is very remarkable if we refer to current opinions about 

 the state of gases in the blood, according to the researches of M. 

 Fernet, classic today. First, the oxygen, chemically united to the 

 hemoglobin, could not be changed as to its proportion by decreased 

 pressure (or increased) ; now what happens is quite different, since 

 the decrease in oxygen is very evident and is quite near the re- 

 quirement of the law governing simple solutions. 



The difficulty appears under an inverse aspect when we con- 



