THE FREQUENCY OF THE PULSE. 55 
If other remote effects of respiration tend to modify the pressure Page 17. 
in the vessels, it is evident that they would co-exist with the above 
and influence it but slightly, explaining the existence of the experi- 
mental discrepancies. 
The Effect of Position of the Body on the Pulse-rate.—The experi- 
ments of Dr. Guy led him to explain the differences in pulse-rate 
following change of position as depending on the amount of muscular 
effort necessary to maintain the positions assumed, and his explana- 
tion, assuming that muscular effort of itself can change pulse-rate, is 
very complete. It is curious that the theory under consideration 
gives an interpretation of the same facts, though very different from 
that of Dr. Guy. 
The following are the most essential facts :—The pulse is quickest 
while standing erect, slowest while lying, intermediate while sitting, 
slow while standing leaning, and while supported entirely, as by being 
bound to a wheel in any position. 
The following is the explanation :—While standing, the only soft 
parts of the body which support the weight of the body are the soles 
of the feet, and the weight is transmitted to them through non-vascu- 
lar and rigid tissues, cartilage and bone. Consequently the blood 
flows freely through almost all the vascular system unobstructed. But 
while lying, most of the weight is supported by highly vascular tissues, 
as the shoulders, arms, thighs, and legs, and consequently much of the 
circulatory system is greatly reduced in capacity from the compression 
‘it experiences, and considerable resistance to the flow of blood is 
introduced into the system, the fall of tension is retarded, and the Page 18. 
pulse therefore rendered slower. 
In sitting, an intermediate condition is the result and an interme- 
diate rate of pulse is produced. 
Leaning while standing, and entire support on a wheel, both by 
introducing resistance from compression of soft parts, tend to make 
the pulse slow. 
Thus, according to Dr. Guy’s assumption, the slow is the normal 
pulse, and the quick the induced; upon the fall of tension theory the 
reverse is the case. The occurrence of bed-sores and the paleness of 
a compressed part prove that pressure disturbs the uniformity of the 
circulation. 
The rapid pulse after a meal, during digestion, depends on the 
relaxation’ of the vessels of the alimentary canal while its functions 
are being performed. 
: 7 4’ 
aie! 
—S 
Ad . 
Jk ile 
el a 
aT 
nL = fa 
e 4 
In a paper on cardiograph tracings* from the human chest wall, 
* Since writing the paper referred to, a further comparison of tracings has 
shown me that in the slow pulses taken while lying, I mistook the primary systolic 
