Stature. — Bryan Robinson* has some speculations and calculations upon this cause, which deserve to be classed with the fanciful conceits of Floyer. They profess to be strictly founded upon observation ; but their fallacy will be apparent, when it is stated that the important element of age is altogether over looked. Falconert follows the example of Bryan Robinson ; and more recently M.Ra meaux $, in a letter addressed to M. Quetelet, pursues the same unprofitable inquiry. The observations, 64 in number, were made by M. Pingrenon, an army surgeon. The subjects examined were all healthy soldiers, placed in similar circumstances, which circumstances, however, are not specified, nor are the ages mentioned. The ordinary range of age in soldiers of the same regiment is quite suffi cient to account for the very slight differences of frequency which M. Rameaux attributes to stdture. How slight that difference is will be seen from the following comparison :—Stature, 5 feet 6i inches ; pulse, from observation, 61.43 : stature, 5 feet 9 inches ; pulse, also from observation, 62.62. The calculated num bers are 64.06 and 63.§ The effect of stature on the pulse has yet to be determined, and it will require a large assortment of observations made on persons of the same sex and age, at the same time of the day, in the same posture of the body, and placed in all respects under the same circumstances.
Posture.— No part of the subject of the pulse, not even excepting its diurnal vari ations, has been more carefully examined than the influence of the posture of the body. Though the broad fact, that the pulse in disease is affected by change of posture, seems to have been familiar to the ancients, the first re corded experiment on the healthy subject was made by Bryan Robinson II, who obtained the following numbers :— Standing, 78 ; sit ting, 68 ; lying, 61. Dr. Macclonnell is the next person who devoted his attention to this subject, and who appears, from his own state ment, to have been engaged upon it so early as the year 1784.1r Falconer, in his work published 1796, investigated the subject more carefully, and states, that " the result of twenty-one accurate trials, made on different days and at different times of the day, all coincided to prove the greater frequency of the pulse standing, than sittino. or lying.", The greatest difference observedWas 13 beats in a minute, and the least difference one beat. Each of these, however, occurred once only. The average difference between the above postures was about six and a third in a minute." He adds, " The pulse in health is, as far as I can find, the same in a sitting as in a horizontal posture." Dr. Knox of Edin burgh*, however, has examined the effect of posture on the pulse still more closely than the authors jiist mentioned. In his first
memoir, published in 1815, he says, " During the morning, the mere change of posture, from the horizontal to the erect, shall increase the pulse by about 15 or 20 beats. At mid day this increase shall be 10 ; and in the evening 4, or 6." In his second essay, pub lished in 1837, Dr. Knox gives the results of actual experinient. Nick t, in 1826, and Dr. Graves T, in 1830, also examined the subject experimentally. It is unnecessary to pursue the history of this department of the pulse into greater detail, as the fact that the pulse is greatly influenced by posture is now familiar to all medical men. The exact amount of the change due to this cause will, perhaps, be best displayed in the average results obtained by the writer from a large number of facts ob served by hiunself. § The following averages were derived from observations on 100 healthy males of the mean age of 27 years, in a state of rest, unex cited either by food or exercise, and, for the rnost part, between the hours of 12 and 2 P. M. : — Standing,18'90 ; sitting, 70'05; lying, 66'62.11 Difference between standing and sitting, 8'85 ; between sitting and lying, 3'43 ; and between standing and lying, 12.28.
These are the average results, from which, however, the extremes are very widely sepa rated ; for the difference between standing and sitting ranges from 26 to 0 ; that between sitting and lying, from 18 to 0 ; and that be tween standing and lying, from 44 to O. The numbers in the observation, at the highest extreme of the scale, were as follows : — Age, 20. Standing, 98 ; sitting, 72 ; lying, 51 : differences, 26, 18, and 44.
To the general rule that the pulse is more frequent standing than sitting, sitting than lying, and, ciforliori, standing than lying, there are several exceptions. Thus there were 5 instances in which there was no difference between standing and sitting ; 19 in which there was no difference between sitting and lying ; and 2 in which the pulse had the same frequency standing and lying. Again, the pulse was more frequent sitting than standing in 3 instances ; lying than sitting in 11 instances ; lying than standing in 5 in stances. The total number of instances, in which exceptions to the general rule occurred, was 34, or one-third of the whole.
If we exclude all exceptions to the general rule, and deduce an average from the 66 ob servations in which the pulse had what niay be termed its normal character, we obtain the following numbers : — Mean age, 27 ; standing, 81.03 ; sitting, 71.12 ; lying, 65.62 : differences, 9'91, 5'50, and 15'41.