Compressed Air; CX Poisoning 719 



o'clock; he dies then. When the muscles were pinched, they con- 

 tracted slowly and strongly as if with cramps. 



So in the animal which had been bled the symptoms appeared 

 much more slowly than in the healthy animal. That is the effect 

 both of the general weakening he had undergone and of the di- 

 minished quantity of blood, which, since it contained a smaller- 

 quantity of oxygen, could carry this dangerous agent to the spinal 

 cord only in smaller proportion. 



It would be premature to dwell at this moment on the part 

 played by the blood in oxygen poisoning. This question will recur 

 in a much more significant manner when we have studied the 

 experiments made on dogs, which I shall now report in detail. 



When I used dogs as experimental animals, my special purpose 

 was to investigate the proportion of oxygen contained in the 

 blood when the convulsive symptoms occurred. I intended also to 

 continue at the same time, thanks to the use of superoxygenated 

 compressed atmospheres, the research of the proportions estab- 

 lished in the living animal between the tension of the oxygen in 

 the respiratory medium and the oxygen content of the arterial 

 blood, proportions studied in Subchapter III of Chapter I up to 10 

 atmospheres of air only. 



The experimental animal was fastened on his board as is ex- 

 plained in the subchapter just mentioned. To succeed in making 

 him breathe compressed oxygen, I had recourse to a special device, 

 not having at my disposal the quantity of oxygen necessary to 

 compress this gas to several atmospheres in a receiver of 150 

 liters capacity. 



I fixed in the dog's trachea a metallic tube as wide as possible, 

 and connected it with a rubber bag having a capacity of about 30 

 liters. This bag was placed beside the animal, and the air injected 

 into the chamber by the pump compressed both the oxygen and the 

 animal at the same time. The experiment never lasted long 

 enough for the dog to exhaust the oxygen entirely. But as the 

 expirations were made into the bag, carbonic acid was stored up 

 there, which consequently accumulated also in the blood. And so 

 we should not take account of the proportion of this gas shown 

 by the analyses; I thought, however, that I should indicate it as 

 a matter of information in the account of the experiments. In 

 a certain number of cases, to avoid this accumulation, I attached 

 to the tube which went from the trachea to the bag, a flask in 

 which the superoxygenated air bubbled in a solution of potash; in 

 other cases, the solution was in the bag itself. These experiments, 



