Diving Bells and Suits 375 



In regard to the general phenomena of metabolism, M. Bucquoy, 

 after analysing all works preceding his and showing their contra- 

 dictions, at least apparent, declares that he: 



Is inclined to believe that in compressed air the respiratory com- 

 bustions increase; but the bases on which they have tried to establish 

 this idea lack solidity, and the question must be re-examined. 



Dr. Foley 2L> has written an odd pamphlet on our subject, which 

 is often quoted and praised. He had observed the symptoms of 

 the caisson-workers at the time of the construction of the bridge 

 of Argenteuil over the Seine in 1861; the maximum pressure had 

 not gone above 3V2 atmospheres. I shall begin by quoting a few 

 of the most characteristic passages in which M. Foley describes 

 and at the same time explains the phenomena experienced in com- 

 pressed air: 



In the caissons all sounds have a metallic tone which shakes your 

 brain; and when one speaks, he makes the base of his skull vibrate as 

 a trumpet would do. 



Let us explain these phenomena. By flattening all of our mucous 

 membrane which is exposed to the air, the compressed air makes" our 

 pharyngo-laryngial and bucco-nasal cavities larger and more sonorous 

 through the bones. 



Moreover, for the vibration, it gives to the edges of the larynx, 

 the tongue, the lips, the soft palate, and even the nostrils, tensions 

 which are greater in proportion to the increase in its density. We 

 must therefore not be surprised that all these organs raise the pitch of 

 the sounds which they produce .... Because of the weakness of our 

 lips, we all lose the power to whistle in compressed air. 



Some persons feel that taste and the sense of smell are weakened 

 or entirely lost in compressed air. 



The flattening of the mucous membrane which is exposed to the 

 air, which makes impossible any hemorrhage of the respiratory tracts 

 and cures suddenly (though not without pain) coryza and hoarseness, 

 explains all these data perfectly. How could a withered, shrivelled 

 organ collect any savors? 



Our skin is more substantial than our mucous membrane; in spite 

 of that the caissons affect it. Its papillae, like those of the nose and 

 tongue, become less sensitive, and many workmen, whose hands, how- 

 ever, are very callous, find their sense of touch less sure in compressed 

 air ... . 



In this same medium, our pulse soon becomes filiform and even 

 imperceptible. The venous pressure soon fails, our circulation flags, 

 but our tissues do not become livid; the contrary is more likely to 

 take place. 



That is because the great tension of the air, favoring the combin- 

 ation of the oxygen with the blood, as with all the other combustibles, 

 makes it so rich that it comes out of our veins as ruddy as out of our 

 arteries. What loss of color would be possible with such a liquid? 



