Sudden Changes in Pressure 881 



the organs, in which inflammatory lesions like those described in 

 Experiments DXXVI and DXXXIV preceded it. 



There now remain to be explained at the same time the initial 

 cause of these cases of paralysis of greater or less length, and the 

 reason for the almost immediate death which so often occurred. 



Let us say next that the hypothesis of M. Bouchard is not at all 

 verified. We have indeed sometimes found the stomach and intes- 

 tines slightly distended by gases; but, besides the fact that this 

 distention has never been very great, we have never seen in the 

 lungs or nervous centers the congestions and hemorrhages to which 

 sudden death is due, according to this author. Furthermore, in all 

 cases, we have noted the persistence of the heart beats, and there- 

 fore we must set aside also the idea of syncope. 



We can go still further. The evident proof that the symptoms 

 which attack decompressed animals are not due to abrupt oscilla- 

 tions of the blood which has been driven back by sudden expansion 

 of the intestinal gases is easily drawn from the experiments re- 

 ported in Chapter IV. We see indeed that dogs could be brought 

 in a few minutes from 7 or 8 atmospheres to normal pressure with- 

 out showing symptoms similar to those which have just been de- 

 scribed, with which it is impossible to confuse the phenomenon of 

 oxygen poisoning, of which they presented the strange and terrible 

 picture. 



But the true cause of all these symptoms was shown very clearly, 

 and the hypothesis of MM. Rameau and Bucquoy (see page 501) 

 received the strongest confirmation from our experiments. The 

 gases of the blood, as the professor of Strasburg had foreseen, are 

 liberated under the influence of sudden decompression, and then 

 cause symptoms comparable to those of an injection of air into the 

 veins. But the phenomenon is more varied and complex than the 

 learned physicist could have thought it. 



In the first place, it is not the three gases of the blood, as he 

 thought, that thus regain their gaseous form. We might have 

 foreseen this result, because our previous researches (Chapter II, 

 Subchapter III) had showed us that the proportion of the oxygen 

 is hardly increased by pressure, and that of the carbonic acid is not 

 increased at all. We were therefore in a position to state, and 

 we might have thought that we had the right to do so, that the 

 gas which would threaten life on being liberated would be ex- 

 clusively the one the proportion of which was considerably in- 

 creased in the blood, that is, nitrogen. 



This conclusion could also be drawn from the experiments of 



