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48 THE LAW WHICH REGULATES 
Got up at 12 night, and in bed in Jess than a minute. A glow came 
on at 12.6. 
Experiment III. Temperature of air 52°5° F. To show that the 
change in pulse-rate did not depend on the effort of getting into bed. 
11.10 P.M. 
11.15 
11.30 
11.45 
12 NIGHT 
Experiment conducted exactly as the first. Nude, lying on the right 
side, at 11.7 p.m. Got up at 11.26 p.m., put on night shirt, took it off 
again and lay down again on floor. Got up again at 11.45'5” and went 
into bed, in night shirt. A glow came on at 11.54'5” p.m. 
From these observations it is apparent that the effect of simply 
altering the condition of the cutaneous vessels, by varying their rela- 
tions to external agencies, varies the pulse-rate in a definite manner ; 
and thermometric results show that on warming the skin, as by covering 
it with bad conductors, the vessels are increased in calibre and the 
arterial resistance reduced. These experiments therefore show that 
reducing the resistance quickens the pulse. 
Marey’s own observations, specially as they are recorded mostly by 
the graphic method, are of themselves sufficiently convincing on this 
point. He compressed the abdominal aorta of a horse, per rectum, 
and found the pulse thereby rendered much slower. The same result 
followed compression of the human femoral arteries. 
The quickened pulse produced by the Turkish bath (in one case 
reaching the extreme rapidity of 172 in a minute on myself), is well 
known; as is the slow one following a cold bath, as shown by Drs: Bence 
Jones and Dickinson. 
From these many facts, all tending in one direction only, it may be 
stated that the rapidity of. the pulse varies inversely as the resistance 
to the flow of blood from the arteries. 
Qnd. The relation of the pulse-rate to the amount of blood in circula- 
tion, or to the blood pressure wm the artertes. 
The following experiments were made :— 
