750 Experiments 



Experiment CCCIX. March 7. Albino rat. 



Rectal temperature 39.6°. 



Kept for three hours in compressed air at 12 atmospheres, above 

 a potash solution which absorbs the carbonic acid as it is formed. 



Withdrawn suddenly, its rectal temperature is only 35.5°; it dies 

 quickly with air in its heart. 



Its liver does not contain sugar; much glycogenic material. 



Experiment CCCX. March 15. Albino rat; rectal temperature 

 39.9°. 



At 12 atmospheres of air for 3 hours, with potash. 



Withdrawn; temperature 37.2°; dies like the rat in the preceding 

 experiment. 



No sugar in the liver. 



In summary, consumption of oxygen, production of carbonic 

 acid and urea, breaking down of glucose in the blood, all chemical 

 phenomena which can be measured easily, appear to be consider- 

 ably slowed down by the action of oxygen under high tension. And 

 as these are the phenomena which determine the production of 

 heat, it is not surprising to see that the temperature of the animals 

 drops considerably. Nor is it astonishing to see that death is the 

 consequence of such a depression in the intensity of the physico- 

 chemical acts of nutrition. 



But the violent excitation, the constant convulsions which ac- 

 company this death are still unexplainable by the depression alone; 

 still less explainable is the persistence of the symptoms after nor- 

 mal pressure has been restored. In fact, in studying diminished 

 pressure, we have noted a diminution of the chemical acts, 

 analogous to what increased pressure revealed, and yet the con- 

 vulsive struggling which precedes death by rapid decompression is 

 in no way comparable to the violent convulsions due to oxygen and, 

 furthermore, the return to free air marks irrevocably the end of all 

 these symptoms. 



This shows then that during compression the regular chemical 

 acts of nutrition have been not only slowed up, but also modified; it 

 is supposable that the result of this deviation has been the forma- 

 tion of some substance capable of playing a toxic part, a substance 

 which, persisting after decompression, would continue to cause the 

 symptoms and might bring on death, a substance the elimination or 

 destruction of which would be necessary for a return to the state 

 of health. 



The chapter especially devoted to the study of fermentations 

 will confirm us in this idea, and will even permit us to express it 

 with more precision and clarity. 



