502 Historical 



admit both the visceral congestions and the escape of the free gases 

 from the blood. 



But no one has seen this escape, since no experiment has been 

 made. And what are these free gases? The three gases of the 

 blood and especially the oxygen, as M. Bucquoy indicates? Nothing 

 proves it; how can we believe that the oxygen, which combines so 

 easily with the tissues, can become gaseous again, and present a 

 serious, unconquerable obstacle to the circulation of this blood 

 which usually absorbs it so rapidly, and into which one can inject 

 it in large quantities without danger? Then how does the gas act 

 when it is freed? By obliterating the vessels? By causing hemor- 

 rhages? And how can it be that the symptoms are only the excep- 

 tion, even above four atmospheres? Could one not deny the truth 

 of the hypothesis itself, by maintaining that, if it must be admitted, 

 all the workmen decompressed at the same time should have their 

 blood like the charged water which escapes from the uncorked 

 bottle of which M. Bucquoy speaks, and should consequently be 

 stricken simultaneously? 



We see, although it is probable a priori, and true as stated in 

 advance, the theory of free gases is far from being proved today. 

 Even for those who expressed and supported it, it is mingled with 

 other theories, and nothing very definite is evolved from the sum- 

 mary which we have just made. 



