THE FREQUENCY OF THE PULSE. 47 
It is thus seen that the blood pressure need not depend on the 
arterial resistance, but if the pressure does not vary, the pulse-rate 
must do so. 
A desire to arrive at the genuine value of this theory of Marey’s, 
led me to make experiments similar to his own, as to the accuracy of 
his fundamental facts. My observations were divided into two series, 
to find,— 
1st. Whether the pulse-rate was related to the capillary resistance. 
2nd. Whether the pulse-rate depended on the pressure of the 
blood in the arteries. 
These points will be considered separately. 
Ist. The relation of the pulse-rate to the arterial resistance. 
The effect of exposing the surface of the body to the influence of 
different temperatures, whereby, as it has been my endeavour to prove 
elsewhere,* variations in the calibre of the eutaneous vessels are pro- 
duced, was carefully examined and the following tables embody my 
results, the curves being those of changes in pulse-rate. 
Ezperiment I. Temperature of the air 515° F. Nude at 11.57 P.M. Page 5. 
Lay down on floor, carpeted, on right side, at 11.58 p.m., with head on 
Nieut 50 55 60 65 
————_ 
foot-stool. Did not feel cold. Got up and put on night shirt and 
jumped into bed at 12.20; a skin glow came on at 12.29... Same 
position maintained in bed as when on carpet. 
Ezperiment IT. Temperature of air 50° F. Nude at 11.40 a.m. and 
lay down on right side. Experiment conducted exactly as the last. 
11.45 
12 NIGHT 
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* “ Proceedings of the Royal Society,” 1869, p. 419. (Suprd, p. 6.) 
