Gases of the Blood 625 



meters, equal to 1/10 of an atmosphere, we see, by combining 

 Tables X and XI, that: 



From 1/10 to V* of an atmosphere, the proportion of oxygen has increased 7.5 

 From Va to Vz of an atmosphere, the proportion of oxygen has increased 5.7 

 From Vz to % of an atmosphere, the proportion of oxygen has increased 4.3 

 From % to 1 of an atmosphere, the proportion of oxygen has increased 2.5 

 From to 1 atmosphere, the proportion of oxygen has increased 20. 

 From 1 to 2 atmospheres, the proportion of oxygen has increased 0.9 

 From 2 to 3 atmospheres, the proportion of oxygen has increased 0.7 



From 4 to 5 dividing by 2 the difference from 3 to 5 = 1.1 increased , Q ' 5 

 From 5 to 6 atmospheres, the proportion of oxygen has increaed 0.2 

 From 6 to 7 atmospheres, the proportion of oxygen has increased 0.2 

 From 7 to 8 atmospheres, the proportion of oxygen has increased 0.1 

 From 8 to 9 atmospheres, the proportion of oxygen has increased 0.1 

 From 9 to 10 atmospheres, the proportion of oxygen has increased 0.1 



Total 23.4 



In other words, these data show that, in the living organism, 

 the absorption of oxygen by the blood increases very rapidly for 

 pressures less than one atmosphere, but very slowly, on the con- 

 trary, for pressures of several atmospheres. Everything seems to 

 indicate that there exists, in the neighborhood of normal pressure, 

 a point of chemical saturation of the oxy-hemoglobin, and that be- 

 yond this point there is added to the blood only the oxygen dis- 

 solved in the serum according to Dalton's Law. This will be veri- 

 fied when I speak of the experiments performed in vitro on blood 

 taken from the vessels. 



At the proper time we shall return to the reflections inspired 

 by these interesting data. For the moment, let us be satisfied 

 with observing that a laborer who works at a pressure of 2 to 5 

 atmospheres has not much more oxygen in his blood than at normal 

 pressure. Moreover, — and this is not to be overlooked in explain- 

 ing the unevenness of the phenomena displayed by the different 

 workmen — I have seen animals which normally had in their blood 

 at normal pressure more oxygen than others at 10 atmospheres; 

 and also in the experiments at diminished pressure certain of my 

 dogs had at normal pressure (See Table X, Experiments 4 and 11) 

 less oxygen than others at a pressure of 56 centimeters and even 

 of 44 centimeters (Experiments 1, 2, 5, and 8). 



2. Carbonic acid. As Table XI shows (Columns 4, 9, 13) , some- 

 times it increases, sometimes it diminishes. Its increase is always 

 very slight (at the most, 9.2 per cent, that is, in actual quantity, 

 3.4 cc. per 100 cc. of blood) ; its decrease was very great (up to 29.7 



