496 Historical 



graphic tracings different in normal air and in compressed air; 

 from my attempts I concluded that very probably Vivenot had not 

 closed his apparatus tightly, and that besides he had left air in it. 

 We understand that it is absolutely useless to dwell on conclusions 

 which are "ganz unphysikalisch," as Panum says very truly. The 

 strangest part of the matter is that this experiment, so oddly con- 

 ceived and so poorly carried out, has been accepted and praised 

 on both sides of the Rhine. Vivenot has made an experiment! they 

 said. And that is enough for many people; for there is a whole 

 school of medicine, the followers of which, of course, have never 

 frequented laboratories, for whom the word "experiment" answers 

 for everything, like the "cream tart" of the comedy. 



Pravaz did not fail to apply to compression the theory which 

 we have already quoted (page 345) in regard to decompression. 

 According to him, the blood is forced more energetically into the 

 interior organs at the time of the inspiration in compressed air, 

 because the exterior pressure acts more vigorously upon the venous 

 system. But, as we have already said, it must be proved that in 

 compressed air the intra-thoracic negative pressure is stronger than 

 at one atmosphere. The conclusions of Vivenot say so, it is true, 

 but I was unable to find the proof of it in his book. 



Finally I shall mention the interesting theory developed by 

 M. Bouchard (page 484). According to him, the abdominal wall, 

 crowded in by the pressure on account of the decrease in volume 

 of the intestinal gases, would tend to resume its shape through its 

 elasticity, and thus would exert upon the abdominal organs a sort 

 of suction, which would cause a storing up of the blood there: the 

 result being visceral congestions and general anemia. For my part, 

 I cannot accept this original idea; it is not only the abdominal wall 

 which is pushed inward; the diaphragm is in the same situation, 

 and we have seen that the vertical diameter of the chest increases. 

 Now it seems to me impossible to admit that these muscular mem- 

 branes present sufficient elasticity to resist the compression and 

 thus act as a cupping-glass: on the contrary, they should, especially 

 the diaphragm, yield to it very passively. 



Nevertheless it is true that, for various reasons, the blood seems 

 to be pushed back from the periphery towards the more deeply 

 situated organs; the result is important modifications in the cir- 

 culation and the metabolism of the different parts of the body, 

 modifications which may have been of great therapeutic value, but 

 from which the health may suffer, when they continue too long. 



