580 Experiments 



animals is summed up in these terms: too low an oxygen tension 

 or too high an oxygen tension. 



Such is the very simple explanation given us by experiments in 

 which we considered the ambient medium much more than the 

 animal. But this too low or too high tension of the oxygen must 

 be studied now, not only in its measure, but in its immediate con- 

 sequences; the animal itself must also be examined with more care. 



The first question which I shall now consider is that of the com- 

 position of the gases contained in the blood of animals subjected 

 to different pressures. 



1 See my Lecons sur la physiologic comparee de la respiration. Lessons XXVII ami 

 XXVIII, p. 496-526. Paris, 1870. 



3 Lecons sur les effets des substances toxiqucs ct medicamentcuses. Paris, 185., p. 125. 



3 Lecons sur les substances toxiques, p. 140. 



* Lecons sur la physiologie de la respiration, p. 51". 



