454 Historical 



air is exclusively physical; he protests against the idea of a chemical 

 change in the respiratory acts; but, aside from this protest, he 

 furnishes no clear idea: 



When the organs of respiration are plunged, so to speak, into a 

 more condensed atmosphere, the lungs will find in the same volume a 

 considerably greater quantity of atmospheric air; after that, they will 

 come in contact, at every inspiration, with a larger mass of atmos- 

 pheric air ... . What will be the result of this addition? This single 

 effect, a greater ease of operation. (P. 15.) 



This reduction of rhythm in the operation of the respiratory 

 movements is purely physical, and in spite of the generally accepted 

 ideas, it is certain that no chemical modification, either an increase or 

 a decrease, is produced in the process of the oxidation of the blood. 

 The air has not been changed in its chemical composition, and the 

 laws which govern our organism have not ceased in their natural 

 action. 



So, whether the atmospheric air is rarified or condensed, there is 

 no modification in the chemical action of respiration; there is only a 

 physical effect upon the performance of this function. But the 

 situation is very different if you change the chemical proportions of 

 the gases of the air. 



One of the effects of the use of compressed air is the increase of 

 the secretions and of absorption. The nervous activity in the excretory 

 and absorbent organs has seemed to me to be derived from the venous 

 circulation, which is always more ample and more complete while 

 the body is being subjected to a higher pressure. (P. 16.) 



In 1855, there appeared the first edition of the book which 

 Eugene Bertin, 110 who was using the apparatuses installed at Mont- 

 pellier by Tabarie, devotes to the study of the therapeutic use of 

 compressed air. This work, as its title indicates, is of particular 

 interest to physicians. Moreover, the author declares in the begin- 

 ning of his book "that he will not discuss physiological consider- 

 ations." And so we shall not pause long over it. 



However, he summarizes his opinions in the following words: 



Compressed air, to whatever degree the compression is carried, 

 can be sustained without danger because of the equilibrium of pres- 

 sure which is established in all parts of the body, exactly as in ordi- 

 nary atmosphere. 



Experimentation demonstrates that at a pressure carried far be- 

 yond the degree needed to cause all therapeutic effects, no modifi- 

 cations in the phenomena of life occur which might interfere with 

 their regularity. 



It is logical to admit that since the decrease of pressure can delay 

 the return of the venous blood to the heart and thus promote stases 

 in the capillary system, an increase of pressure should, on the con- 

 trary, facilitate this return and dissipate these congestions. 



Respiration which is carried on in compressed air, because it 



