464 Historical 



Here, for example, is the key to the discharge of blood which 

 occurs rather frequently from the nose or mouth: 



The mucous membrane, almost bloodless as long as the compressed 

 air acts upon it, fills with blood as soon as the tension ceases, ruptures 

 if it is too thin .... then, momentarily surprised, it recovers its 

 normal thickness after a few painful oscillations. (P. 30.) 



And now for the sensations of heat in the skin, and for the 

 "painful, burning, intolerable itching, which forces one to scratch 

 himself with both hands with impatience, uneasiness, fury, or 

 delirium, which the workmen call fleas": 



As soon as one enters the caissons, he is flattened; the arteries 

 diminish in caliber, and there is abundant perspiration. By all these 

 effects our skin empties and withers. 



As soon as one leaves, on the contrary, merely through the me- 

 chanical power of its elastic fibers, this envelope expands. Unfortu- 

 nately the retractility of their yellow coats keeps our nutritive vessels 

 at their minimum diameter. The result is that a sort of vacuum forms 

 around them. 



Matters being thus situated, when the reaction begins, or in other 

 words, when the blood waves become strong again, our arteries, which 

 previously were isolated, yield easily, regain their former diameter, 

 and even increase it. At the same time, our innumerable cutaneous 

 papillae are considerably swollen by a superoxygenated blood. Then 

 within the thickness of the skin the nerve meshes which are inter- 

 woven with our nutritive vessels, suddenly tugged about inordinately, 

 cause cruel and lacerating pains, whereas on the surface of the skin 

 any contact causes both itching and burning. It is all these simulta- 

 neous pains that cause the "fleas." (P. 33.) 



Finally, the symptoms which attack "the muscles, then their 

 synovial auxiliaries, aponeurotic or articular," are explained in the 

 same way; they are tumefactions, as we have already seen 

 (page 377) : 



Are these swellings of a gaseous, hemorrhagic, or rheumatic 

 nature, as has been stated? No! 



The recompression which always dispels them immediately, the 

 absence of crepitation, of rale, of any coloration under the skin, and 

 of peregrination, and finally the excessive richness of the blood, which 

 excludes any idea of excess fibrin, or, in other words, of an inflamma- 

 tory malady, do not allow us to doubt. These are simply arterial con- 

 gestions without extravasation. (P. 35.) 



M. Foley does not hesitate to predict the brightest future for 

 treatment by compressed air: 



Make (he says) a sedan chair closing hermetically .... Attach 

 to it a safety valve, a blower, and a manometer: in a word, arrange 



