670 Experiments 



We see that in the decompression chamber the circulatory ac- 

 celeration appears quickly, as aeronauts had already observed. It 

 increases considerably at the slightest movements. 



Experiments on animals give evidence of the same sort. They 

 usually show remarkable agreement between the variation of the 

 number of respiratory movements and that of the cardiac beats. 



Fig. 49 — Simultaneous modifications of the number of respiratory move- 

 ments R and the pulse P under the influence of decompression. 

 Cat, Experiment CCXXI. 



Figure 49 gives a remarkable example of this, taken from Ex- 

 periment CCXXI, made on a cat. The line of the pulse is marked 

 P; it corresponds to Column P of the ordinates. The line of the 

 respiration is indicated by the letter R, as is the value of its ordi- 

 nates. The pressures are reckoned on the axis of the abscissae. 



The same agreement, though less constant, is observed in Figure 

 50, which shows the observations made during Experiment CCXVIII. 



Finally, in Figure 51, which gives the strange results of Experi- 

 ment CCXVII, we see that if the number of respiratory movements 

 diminishes with the pressure, the same is approximately true of 



