Summary and Discussion 501 



excess pressure on the brain and the spinal cord from escaping 

 rather rapidly by the narrow passages through which the blood 

 leaves these organs:" and hence the congestions, or rather the 

 nervous compressions. This error in physics really does not de- 

 serve refutation. 



On this subject M. Bouchard has conceived an idea worthy 

 of attention. It might be the sudden expansion of the intestinal 

 gases, originally compressed, which would suddenly expel the 

 blood contained in the abdominal viscera, would drive it into the 

 general circulation, and produce the congestions and the hemor- 

 rhages in the nervous organs (page 486). I confess that I cannot 

 admit that an expansion of gas, in a canal open at both ends, when 

 dealing with walls as extensible as the diaphragm and the ab- 

 dominal muscles, can expel the blood from the liver, the spleen, 

 etc., so violently as to produce such - disturbances. 



Another explanation of the symptoms of decompression has 

 been suggested by M. Bucquoy, and prompted by the lectures of 

 Professor Rameaux, of Strassburg (page 459). Under the effect 

 of pressure, the gases of the blood would increase in quantity, the 

 oxygen following Dalton's Law, the nitrogen and the carbonic acid 

 following a lessened progression, "since they are not drawn in in 

 the inspired air, but engendered by the physical phenomena of 

 life." As a result, at the time of decompression, these gases tend 

 to be liberated again, just as "the carbonic acid escapes from 

 charged water, when the stopper is removed from the bottle con- 

 taining it." And M. Bucquoy mentions, to support this hypothesis 

 so probable in its general features, the emphysemas observed at 

 Douchy, the cure of muscular swellings by recompression, and a 

 very interesting observation which we have reported in full (page 

 460) 



F. Hoppe, as we have seen, had already had the same idea; but 

 he based it only on experiments made on decompression by the 

 pneumatic machine, and brought no personal observation to sup- 

 port his hypothesis (page 455) . 



The idea of M. Bucquoy was accepted by M. Frangois, who, 

 however, seems not to have had a very clear understanding of it, 

 because he speaks of "an amalgamation of the cellular tissue with 

 the air from the blowers, like that of mercury with hog's lard" 

 (page 456) , and by all the authors who followed him, Vivenot (page 

 435), Panum (page 480), M. Gavarret (page 482), M. Leroy de 

 Mericourt (page 483), etc.; M. Foley alone did not believe in it 

 (page 463) . M. Bouchard (page 484) , M. Gal (page 486) , and others 



