Gases of the Blood 935 



that found sometimes in the blood of animals breathing free air; 

 the maximum was 53.6 (Exp. DCXLI), and the visible symptoms 

 of poisoning by carbonic acid do not appear before the blood con- 

 tains 70 to 80 volumes of this gas. Finally, the question cannot 

 even be asked in cases where carbonic acid, far from increasing, 

 diminished in the blood and the tissues. 



This is the time to recall Experiments DCXXIV, DCXXV, 

 DCXXVI, reported in the matter of poisoning by carbonic acid, in 

 reference to the quantity of this gas dissolved in the tissues. They 

 show, in fact, that in the animals of Experiments DCXXXVIII, 

 DCXXXIX, and DCXL, the tissues contained only a small quantity 

 of carbonic acid, hardly, if any, greater than is found there nor- 

 mally. Finally, the urine of asphyxiated dogs released, in presence 

 of an acid, only 15 to 20 volumes of C0 2 (Exp. DCXXXIX, DCXL) , 

 that is, the quantity found on the average in dogs given a mixed 

 diet. 



All this collection of facts shows decisively, then, that carbonic 

 acid plays no part in the death of dogs, which are drowned, 

 strangled, or asphyxiated in a very small quantity of air, and that 

 this part is negligible when asphyxia takes place in larger spaces. 

 Perhaps it would be unwise to apply this last conclusion to ani- 

 mals in which, as in sparrows, the lethal tension of carbonic acid 

 in the air is only from 22% to 26%; here again, however, Experi- 

 ment DCXXVIII C shows that carbonic acid has no great im- 

 portance. 



However, its decrease in the tissues when the asphyxia took 

 place in air freed of carbonic acid or in expanded air (Experiments 

 DCXXVIII D and DCXXIII) may perhaps explain the few differ- 

 ences we noted between asphyxia in closed vessels and asphyxia by 

 decompression, mentioning particularly rigor mortis. 



Subchapter III 

 OBSERVATIONS ON THE GASES OF THE BLOOD 



The numerous analyses of the gases of the blood which I have 

 reported in this book deserve to occupy us some moments, even 

 disregarding considerations relating to barometric pressure. 



I shall say at the very beginning that the high temperature to 

 which I raise the blood in the gas pump permitted me to extract 

 the gases of the blood much more rapidly and much more com- 

 pletely than my predecessors could manage to do. Of course, at 



