90 Experiments 



6 o'clock, all dead; the hearts, which are full of air, can be seen 

 beating; because of the transparency, bubbles of gas can be seen in 

 all the vessels. 



Subchapter IV 



PROPHYLAXIS AND TREATMENT OF SYMPTOMS 

 OF SUDDEN DECOMPRESSION 



Considering these dangerous symptoms, a double question is 

 naturally suggested: how to prevent them, and how to cure them. 



They will be prevented, as common sense suggests and ex- 

 perience proves, by making the decompression slow enough. On 

 this point the experiments summarized in Table XIX give very 

 clear indications. We see, for example, that from 10 atmospheres 

 on, we avoided serious symptoms by giving more than 1 hour and 

 10 minutes to the decompression (Experiments DLXXI, DLXXII, 

 DLXXVII, DLXXVIII). But this is the minimum time, since an 

 hour, in Experiment DLXXIV, did not prevent death. I set aside 

 Experiments DLXXX and DLXXXI, which show a peculiarity that 

 I still cannot explain. 



I did not perceive great differences between the cases in which 

 the decompression was made continuously at the rate of 8 minutes 

 per atmosphere (Exp. DLXXVIII), or 10 minutes (Exp. DLXXVI), 

 and those in which it was made by sudden drops with intervals of 

 rest (Exp. DLXXII, DLXXVII) . Besides, the data are not numer- 

 ous enough to permit conclusions in favor of either of these 

 methods. 



But it is certain that beginning with 10 atmospheres one cannot 

 be sure that a dog will be out of danger unless the decompression 

 is given a duration of at least 12 minutes per atmosphere. We 

 shall return to these data in the third part of this work. 



And now for the second question. The decompression was made 

 too quickly. Gases escape into the blood, which obstruct certain 

 vessels and threaten the experimental animal with death. Evi- 

 dently I should have thought of causing them to be redissolved by 

 subjecting the animal to a new compression with the purpose of 

 decompressing him with controlled slowness. And that is what I 

 did in the two following cases: 



Experiment DLXXXVII. October 18. Dog of Experiment DXXXVIII. 

 It is paraplegic as a consequence of a sudden decompression from 

 7 atmospheres; the paraplegia began at 3:21. 



