Increased Pressure 1021 



the improvement due to treatments. For real proof, one would 

 have to experiment on individuals in good health. 



Subchapter II 

 SUMMARY AND PRACTICAL APPLICATIONS 



1. High Pressures. 



The discovery of the toxic action of oxygen at high tension cer- 

 tainly constitutes the most interesting and most unexpected part of 

 this long work. Experiments made on animals and plants, on 

 beings dwelling in the air, as well as those dwelling in the water, 

 on beings of complicated structure, as well as on microscopic 

 monocellular animalculae, and on anatomical elements separated 

 from the body, have shown in the clearest way that above a certain 

 oxygen tension of the ambient atmosphere life becomes impos- 

 sible, and that death may come with remarkable rapidity. 



In warm-blooded animals, the violent convulsive phenomena 

 which we have described (p. 741) appear at once above 20 at- 

 mospheres of air; very speedy death takes place above 25 atmos- 

 pheres; but painful effects are clearly felt at 6 atmospheres, as we 

 have seen by an indirect method (p. 713) . 



We have given abundant proof that they are the consequence 

 not of the barometric pressure as a physico-mechanical agent, but 

 of the increase in the tension of the ambient oxygen. I refer you 

 for all these data to Chapter IV, subchapter I, where they were 

 studied in detail. I have given there not only the description of 

 the symptoms of poisoning by oxygen, specifications of the lethal 

 dose of exterior oxygen, expressed in tensions, but also that of the 

 oxygen content of the blood which corresponds to the different 

 stages of the exterior phenomena: death occurs quickly when the 

 proportion of this gas has increased by a third in the arterial blood. 

 I also showed there the apparently paradoxical result that under 

 the influence of greater oxygenation of the blood, the tissues oxidize 

 less, the organic combustions lose energy, the production of car- 

 bonic acid, the excretion of urea, the intra-sanguine metabolism 

 of sugar are impeded, and that consequently the temperature drops. 



These data cease to seem odd when linked with those given in 

 Chapter VI. All the anatomical elements, it is shown there, undergo 

 the formidable effects of compressed oxygen (p. 839) ; the micro- 

 scopic organisms which cause true fermentations, are killed by 



