492 Historical 



which a stay in the bells seems to produce. On this point then, it 

 hardly seems possible to reach any conclusion. 



The observations of Vivenot on an increase in body tempera- 

 ture, of from 0.1° to 0.4°, do not seem to me at all convincing. 



As to the production of carbonic acid in a given time, we shall 

 speak of that in the next section. 



Innervation. It is very difficult to see, in the accounts of the 

 authors, any clear indications in regard to sensory functions. Taste 

 and smell are disagreeably affected by the impurities in the air 

 of the caissons, and the ear is affected by the distention of the 

 tympanic membrane. 



They do not agree in regard to the functions of the brain. Col- 

 ladon (page 357) mentions a stimulation which resembles intoxi- 

 cation; M. Junod (page 414) states that "the functions of the brain 

 are stimulated;" M. Foley, when he left the caissons, it is true, was 

 attacked by an excessive cerebral excitation which made him 

 "catch himself in the very act of babbling, in spite of all his 

 efforts." J. Lange (page 477) states that constantly, even in the 

 apparatus, "one experiences an activity and coolness of mind which 

 did not exist before." On the opposite side, Dr. Francois says that 

 especially at the beginning one feels a sort of drowsiness, and 

 according to G. Lange, the only phenomenon which one can note 

 is "a feeling of calmness generally followed by a desire to sleep." 



B. Phenomena Due to Decompression. 



Their severity depends, as we have said, upon two factors to 

 which it is proportional: the degree of pressure reached, the speed 

 of the decompression. 



Up to 2 atmospheres, no symptom seems to appear in the work- 

 men. Above that, there appear more and more frequently 

 cutaneous itchings, "puces" (fleas) , which finally cause very keen 

 pains; they are much more common in caisson workers than in 

 divers. Then come painful swellings of the muscles, particularly, 

 according to the accurate note of M. Foley, of those, muscles which 

 worked hardest during the stay in compressed air; at the same time, 

 periarticular pains. Not until the pressure is above 3 atmospheres 

 do really serious symptoms occur: sensory disturbances, blind- 

 ness, deafness, disturbances of locomotion and general sensitivity, 

 especially paralysis of the lower limbs, the bladder, the rectum, 

 and, much more rarely, the thoracic members; cerebral disturb- 

 ances, loss of consciousness; finally, sudden death. 



These symptoms do not appear until after a few minutes and 



