436 



Historical 



chapter; here, we shall mention only observations relating to the 

 physico-mechanical phenomena of circulation and respiration. 



Respiration. The first phenomenon discussed is the enlarge- 

 ment of the pulmonary cavity in compressed air: 



Respiration is always deeper than at normal pressure. This effect 

 often lasts for 24 hours or more and increases with the repetition 

 of the air treatments. In one person whose inspiration, under normal 

 pressure, amounted to 400 to 700 cc. (an average of 480 cc), the first 

 treatment of 35 cm. raised it from 650 to 800 cc. (average 750 cc); the 

 second took it on the average to 900 cc. 



The frequency of the movements had fallen from 13 - 14.5 to 11.5 

 per minute. (P. 153) 



Here, moreover, is a table which expresses the modifications 

 shown by respiration in normal air and in compressed air, follow- 

 ing different voluntary rhythms of respiration: 



As for the respiratory rhythm properly so-called, Panum states 

 that "the relative duration of the inspiration and the expiration 

 is similar in compressed air and at normal pressure." And in sup- 

 port of this statement, which contradicts what we previously re- 

 ported on the authority of Vivenot, he gives a tracing of respiratory 

 movements directly recorded. 



Circulation. Panum reports the observations of Vivenot and 

 Sandhal, and admits the slowing down of the pulse. He tried to 

 make experiments on two dogs to study the modifications of the 

 manometric pressure of the heart; but they gave no result. 



The decrease of the blood flow in the capillaries is proved, 



