This table, though obviously based upon a number of facts too small to furnish exact averages, may be taken as presenting an ap proximation to the truth. It indicates a progressive decline from infancy to adult age as the true law of the pulse, — a law which would probably be clearly displayed by ave rages deduced from a large number of facts.
The following table presents the number of the Pulse at each quinquennial period through out the whole of life. The averages for the first eight periods are founded each on 50 observations, of which half were made on males, and half on females. The average for the period from 76 to 80 is deduced from the same number of facts similarly divided. For most of the other periods the averages are derived from forty observations, twenty on males, and twenty on females. Where the number of observations is less than this, it is stated in a note.
The pulse of the aged has been very care fully examined by Leuret and Mitivie*, Hourmann and Deschambrel-, and Dr. C. W. Pennock.t According to the observations of the first-named authorities, the average fre quency of the pulse in 27 males and 34 females, each sex being of the mean age of 71 years, was, in round numbers, 76. The number would have been somewhat higher but for the exclusion, as abnormal, of pulses exceeding 100. Dr. Pennock's observations on 170 males and 203 females, of the mean age of about 67 years, give as the average frequency of the pulse, 75 beats. The observations of Drs. Hourmann and Deschambre having been made solely on females, are not avail able in this place. It will be seen that the results deduced from the observations of Leuret and Mitivie, and of Dr. Pennock do not differ materially from the numbers in the table.
As it is extremely difficult, even for those who are most in the habit of dealing with figures, to remember the exact results of a series of averages, it may be useful to lay down a near approximation to the average numbers at the several leading periods of life. This is done in the following table.
The want of regularity in this table arises from the same cause as in the former — the comparatively small number of facts. A regular and progressive decrease in the mean values, however, would probably not be ob tained by any number of observations which it is in the power of a single individual to bring together, whether as the result of his own inquiries, or as derived from the recorded researches of others. But the figures of this
table will still suffice to indicate a law of pro gressive decrease from the beginning to the end of life, with an increase during the period of decrepitude. The decrease during the first four quinquennial periods is very rapid ; during the fourth and fifth the number re mains nearly stationary ; from the fifth to the sixth period there is again a fall of a few beats ; but during the remainder of life (from 25 to 80) a very slight difference exists be tween the several quinquennial periods ; the difference between the averages amounting to only 4 beats, between the minima to 10 beats, and between the maxima to 20 beats. The average rise during the period of decrepitude amounts to 7 beats. t SEX. — The recorded observations on the pulses of males and females respectively during the early periods of life are few in number. At birth, according to the observations of Quetelet, there is a difference of only one beat, the average number in males being 136, and in females 135. The following table contrasts the two sexes at those periods at which the number of recorded observations, added to those made by the writer of this article, are ferred from the following comp.arison of the extreme and mean results derived from 25 and 50 observations respectively on the pulses of healthy males.
sufficiently numerous to furnish a fair ave rage.* It would appear, then, that even at a very early period of life, the difference of the sexes is marked in the pulse t ; that this difference is very inconsiderable in infancy, but well marked in childhood.
The following table presents, in septennial periods, the results of the observations of the writer during the whole of life. Each average is founded on 25 observations, made with great care, in apparently healthy per sons, fasting, in a state of rest, in the middle of the day, and in a sitting posture.