380 Experiments 



symptoms, often death, at 7 atmospheres, except the animals of 

 Experiments DXLIX and DLII which resisted the decompression 

 of 7V2 atmospheres, and that of DLV which survived even SV2. 



This last animal, from this point of view, is particularly interest- 

 ing. In a series of sudden decompressions, beginning with IV2 at- 

 mospheres (Exp. DLII and DLIII) , then with 8 atmospheres (Exp. 

 DLIV and DLVI), and even 8V 2 atmospheres (Exp. DLV), it 

 showed no sign of sickness. Then four months later, decompressed 

 from 8 atmospheres, it died in less than a half -hour (Exp. DLX) . 

 During the first series of experiments, it was thin and in very bad 

 shape; at the time of the last, on the contrary, good care had made 

 it fat and healthy. 



Must we attribute the difference in results to this difference in 

 condition? The cause, purely physico-chemical, which we shall be 

 compelled to attribute to the symptoms of decompression, does not 

 lend itself to this interpretation. Furthermore, Experiment DLVII 

 shows us a dog in just as bad a condition, at least, which at the first 

 trial, died from a decompression beginning with 8 atmospheres. 



No less inexplicable is the resistance of the puppies of Experi- 

 ment DLXXXI when the adult dog placed beside them during more 

 than 5 hours (Exp. DLXXX) died immediately after a slow decom- 

 pression, beginning with IV2 atmospheres. 



But setting aside these irregularities which may suggest im- 

 portant considerations in practice, let us now examine the symp- 

 toms in themselves. 



In sudden decompression beginning with 8 atmospheres and 

 above, we have seen almost always a practically instantaneous 

 death. It appeared also, but more rarely, in decompressions begin- 

 ning with 7 to 8 atmospheres. Generally then the symptoms con- 

 sisted of a paralysis of the hind legs, a paralysis sometimes slight 

 and transitory, sometimes persisting for several days, sometimes, 

 finally, rapidly ascending and involving death by asphyxia after 

 several hours. 



The cases in which the paralysis receded were, as one might 

 expect, the limited cases (Exp. DXXX, DLXXI, DLXXVI) ; the 

 limbs alone had been affected; voluntary movement alone had been 

 lessened. These symptoms disappeared of themselves in less than 

 an hour; all that I saw last longer continued till death. 



When death occurred, we usually found to explain it and to 

 explain the more or less complex phenomena which had preceded 

 it, a more or less extensive softening of the spinal cord, much ad- 

 vanced in the lumbar regions, and making progress in the rest of 



