Theories and Experiments 461 



He first dwells at great length on the confinement to which the 

 laborers working in the caissons are subjected. The carbonic acid 

 which is produced there must, in his opinion, play a great part, 

 and recalling the tinglings and the burning of the skin described 

 by Herpin (of Metz) he thinks: 



That this phenomenon might very well be the cause of the burning 

 and itching of which the workmen complain and which MM. Pol, 

 Mathieu, and Frangois have noted, which the workmen call their fleas. 



Likewise, the effects of the bath of carbonic acid which accelerates 

 the circulation may give us the reason for the divergence of opinions 

 which we have reported between MM. Pol, Mathieu, and Blavier, on 

 the one hand, (the first two having observed a slowing down of the 

 circulation in compressed air, the third having noticed no difference 

 in three persons) and on the other hand, M. Franqois, who noted a 

 constant acceleration of the circulation. (Vol. XVI, p. 445.) 



As to the redness of the venous blood, observed by Pol and 

 Watelle, he refuses to accept their shrewd explanation. He repeats 

 with Francois that "it is not an excess of oxygen which is sent into 

 the caissons but an excess of atmospheric air." He even goes 

 further: 



As we have proved, the oxygen of the caissons was considerably 

 diminished by the respiratory absorption and combustion; since the 

 carbonic acid is a hindrance to hematosis, how could the venous 

 blood be oxygenated? We must seek some other reason for the 

 redness of the blood. The conditions of the medium which we are 

 discussing give reason to assume the formation of carbon monoxide, 

 which would explain this phenomenon. (P. 447.) 



This carbon monoxide would be produced, according to our 

 homeopathist, by respiration in air with a low oxygen content. 

 Such is the cause of the symptoms attacking the workmen: 



Since the authors saw these symptoms appear only after decom- 

 pression, they have attributed them all to this transition. 



He then reaches the study of decompression; and he compares 

 what takes place in workmen with the effects of ascent into the 

 lofty regions of the atmosphere. There is a great difference, how- 

 ever, he says, namely: 



As it is the normal pressure of the air which keeps the fluids in 

 the vessels, it is rare that the hemorrhages which are frequent in 

 ascents appear when the men leave the caissons. (Vol. XVII, p. 37.) 



Besides, the effects are more serious than those of ascent because 

 the compression is greater, because the decompression is more 

 rapid, because it acts upon men in a manifestly morbid condition, 



