940 Experiments 



result, not only from a lessened quantity of corpuscles or even of 

 hemoglobin, but from an alteration in the latter, which becomes 

 less fitted to absorb oxygen. This is a very important subject for 

 research, the study of which, at my suggestion, Dr. Legerot 6 has 

 begun. 



At any rate, setting aside very young animals and sick ones, it 

 is certain that great differences exist between different animals of 

 the same species in regard to the oxygen content of their blood. 



On the other hand, in the same animal, considerable changes in 

 the circulatory and respiratory rhythms may greatly change this 

 oxygen content. I have already noted these facts in the chapter 

 which deals with the discussion of my method of analyzing the 

 gases of the blood. Experiments CLVI, CCLXXXVIII, and 

 DCXXXIX, listed in the preceding table, are quite characteristic 

 from this point of view. 



Carbonic Acid. Carbonic acid has been extracted from the blood 

 in proportions even more variable than those of oxygen. The 

 extremes, eliminating exceptional data, have been 50.8 (Exp. 

 CLXXXVIII) and 33 (Exp. CCLXXXI). There were 36 analyses 

 giving from 30 to 40, 32 giving from 40 to 50, 3 above 50 ? and the 

 general average was 40.4. 



The acceleration of the respiration, especially when it is carried 

 on directly by the trachea, lessens the quantity of C0 2 in the 

 blood in a proportion that is often enormous. I have already men- 

 tioned these facts in dealing with the experimental criticism and 

 the degree of accuracy which may be attributed to the analyses of 

 the gases of the blood. The data given by our experiments are 

 reproduced in the table above: these are Experiments CLXI bis, 

 CCLXXVIII, CCLXXXII, CCLXXXIII, CCLXXXVII bis, DCVII, 

 DCXXXIX bis, DCLVI. I call attention particularly to Experi- 

 ment CCLXXXVIII, in which the quantity of CO. fell from 41.5 

 to 15.2 by tracheal respiration; and Experiment DCVII, in which 

 an exaggerated respiration, through natural channels however, 

 brought this gas to 19.5. 



So the diminution of the carbonic acid of the blood through 

 exaggerated respiration under normal pressure may reach almost 

 the same degree as in animals subjected to the lowest atmospheric 

 pressures, since Table X gives as averages 29.3 at the pressure of 

 34 cm., 23.2 at that of 25 cm., and even 12.4 at that of 17 cm. 



If we refer to the circumstances of the extraction of the gases 

 by the pump, we shall see that the ease of this extraction depends, 

 as one might have expected, on the quantity of them which exists 



