Chapter IV 



ACTION OF COMPRESSED AIR 

 ON ANIMALS 



Subchapter I 

 TOXIC ACTION OF OXYGEN AT HIGH TENSION 



The experiments reported in Chapter I, Subchapter II, have 

 brought us to this remarkable conclusion, that compressed air, or, 

 to speak more exactly, the oxygen which has reached a certain 

 tension constitutes a dangerous element, often even fatal, for ani- 

 mal life. 



This unexpected revelation, which is deduced from all our 

 series of experiments in such a way as to be convincing to the 

 most suspicious mind, deserved deep study. The symptoms of this 

 unknown sort of poisoning in its different degrees had to be 

 analyzed; the concentrations at which oxygen becomes dangerous 

 had to be determined, both as to its tension in the exterior respira- 

 tory medium and as to its proportion in the interior respiratory 

 medium, the blood; an explanation had to be found for its inner 

 mode of action upon the different anatomical elements. 



This new problem left far behind it in scientific interest the 

 analysis of some modifications in the respiratory and circulatory 

 rhythms hitherto studied by the authors who gave their atten- 

 tion to compressed air. I devoted myself to it at the very beginning 

 with all the concentration of which I was capable. Having demon- 

 strated successively that compressed air acts only by the tension 

 of the oxygen which it contains, and that this oxygen can kill 

 animals rapidly with convulsive symptoms, following the usual 



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