674 Experiments 



recall, in an exaggerated way, the trembling I myself felt. At the 

 extreme limits, when death comes, real convulsions appear, whose 

 violence is in proportion to the strength which the animal then 

 retains. 



When the decompression has been brought on slowly, when it 

 has lasted a long time, when the animal is much weakened and 

 chilled, no convulsions are observed, or they are very slight. I 

 have shown elsewhere that the same thing is true in ordinary 

 asphyxia, in closed vessels. For example, here is an experiment. 



Experiment CCXXXIII. September 17. Two starlings. 



A. One is placed under a bell of 900 cc, inverted over a basin of 

 water. At the end of three quarters of an hour violent convulsions 

 occur, and the bird dies. 



B. The second is put under a bell of 14 liters, also inverted over 

 water. At the end of about 6 hours, respiration seems much affected. 

 Death occurs after 9 hours and 25 minutes, with gradual phenomena, 

 without convulsions. 



The convulsions produced by decompression, by asphyxia, and, 

 I add, by hemorrhage, are merely a violent response of the spinal 

 cord, over-stimulated by a sudden change in the conditions of its 

 nutrition. If the transitions are carefully managed, if there are 

 only slow and progressive changes, we see no more violent symp- 

 toms, no more convulsions. 



The experiments reported in Chapter II, Subchapters I and IV, 

 show that in decompression carbonic acid diminishes considerably 

 in the blood. When death is reached, when convulsions occur, the 

 animal has lost more than two-thirds of it. Very evidently the 

 convulsive phenomena must not be attributed to this gas, as is 

 stated in the theory propounded in 1850 by M. Brown-Sequard, and 

 accepted today by a great number of physiologists. 1 We shall see 

 directly, in another chapter, that carbonic acid is a narcotic of the 

 nerves and the muscles, far from tending to over-stimulate them. 



Here, I simply wish to call attention to the fact that in all the 

 experiments which this learned physiologist has brought to sup- 

 port his statement, the oxygen diminished rapidly to the point of 

 disappearing, while the carbonic acid itself hardly increased in the 

 blood and the tissues. What we have just said is enough, without 

 further insistence, to prove that it is to this sudden decrease of 

 oxygen that we should attribute the medullary excitations and 

 the muscular contractions. 



I think I should add here that in animals killed by decompres- 

 sion, as in animals rapidly asphyxiated or bled to death, one can 



