430 Historical, 



tion which, maintained by the daily repetition of this same influence 

 of the pressure of the air, increases from day to day to a certain 

 figure; moreover, the respiration is easier in compressed air; it be- 

 comes calmer and more complete; and thus certain respiratory dis- 

 turbances are quieted. So whereas in the open air the influence of 

 •the respiration was shown in the curve of the pulse, in compressed 

 air this influence should be weakened,, that is, the curves and arches 

 of the line of the pulse should, under this influence, lose frequency 



Fig. 14 



and intensity, as, moreover, we can see in Figure 14, which, made May 

 1 on an emphysematous patient aged 44, in a at normal pressure 

 shows noticeable variations in the curves expressing the pulsations, 

 which show great difficulty in respiration, whereas, under the in- 

 fluence of compressed air in b, the intensity of the curve has fallen 

 so considerably that the pulse line almost becomes horizontal, and 

 that at the same time there is a greater number of pulsations for 

 one respiration than in a, and by this change the abatement of the 

 previous respiratory difficulty is indicated. 



The existence of this change in the respiratory curve under the 

 influence of compressed air may be considered the rule, and we rarely 

 find the opposite state. (P. 578-580.) 



As to the number of pulsations, Vivenot summarizes in the fol- 

 lowing words 423 observations made upon himself: 



In the morning between 6 and 7 o'clock, when I awoke, my pulse 

 rate was 65.22. After I had breakfasted in bed, this number rose to 

 its maximum, 81.20; at the time of entering the pneumatic apparatus 

 it was only 79.03. Under the influence of compressed air, it fell to 

 between 75.43 and 71.66; on return to normal pressure it was still 

 72.41, and in the course of the day my pulse did not rise to the figure 

 given before my entering the apparatus. 



This decrease in the pulse rate in compressed air was noted 375 

 times in my 423 observations; 18 times there was no change; 30 

 times, an increase in the pulse rate. (P. 532). 



Vivenot observed that the congestion of the vessels of the con- 

 junctiva disappeared wholly or partially through compression. 

 The examination of the retina in a person who had been given 

 atropine also showed him that the vessels of the eye are emptied 

 of blood in compressed air. 



Besides, he made five direct observations upon a tame white 



