756 Experiments 



conditions easy to realize which do not require, as do high pres- 

 sures, the use of expensive and fragile glass apparatuses. 



Finally, it seemed to me that I simply could not neglect these 

 modifications in the circulation and the respiration, which before 

 my time interested so many observers, whose statements, as we saw 

 in the historical part, are far from being always in harmony. I was 

 particularly anxious to measure the mechanical action of com- 

 pressed air, acting upon the gaseous reservoirs of the organism, that 

 is, the intestine and the lung. 



In consequence, the experiments reported in this subchapter 

 will naturally be divided into two categories: in some, the super- 

 oxygenated air will act for only a short time, several hours, a day 

 at the most; in others, its action will be continued until it is ascer- 

 tained whether or not it has any effect. 



1. Short Stay in Compressed Air. 



A. Experiments Made Upon Myself. 



I shall first report the experiments made upon myself with the 

 purpose of investigating on the one hand the respiratory and cir- 

 culatory phenomena, and on the other hand the action of com- 

 pressed air upon the excretion of urea, that is, upon one of the 

 evidences of intra-organic combustions. 



For this part of my researches, Dr. Jourdanet lent me a chamber 

 which he has had made for therapeutic applications, and in which 

 an ingenious arrangement allows one to secure at will an increase 

 or a diminution in pressure. 



This chamber, the general aspect of which is given in Figure 62, 

 measures 2.58 meters in height and 1.46 meters in diameter, and 

 consequently contains about 3*4 cubic meters of air; it is closed by 

 two doors, one inside and the other outside, on rollers guided by 

 grooves; these doors are fastened together, when they are closed, 

 by three long screws, which pass through holes cut through their 

 walls. As they are fitted tightly on the walls of the cylinder by 

 rubber gaskets, there is always one of them closed hermetically, for 

 compressed as well as for expanded air. A rubber tube communi- 

 cates with one or the other of the decompression or compression 

 pumps; communication with the outer air is secured by openings 

 which are not seen in the figure and which are controlled by inner 

 cocks, which the experimenter manages; another cock permits his 

 assistants to make the decompression if any accident happens to 

 him. On both the inside and the outside are precision thermometers 

 and manometers. 



In this apparatus, operating at full speed, in one hour I can 



