Pulse, in animal economy, a term denoting the alternate dilatation and contraction of the heart arteries, in consequence of which the blood, being ejected from the left ventricle of that organ, is impelled into the arteries, so that it may circulate throughout the body :—this incessant motion, or throbbing of the vessels, is distinctly perceptible by the finger.

The various circumstances by which a natural pulse is liable to be affected, are, by Dr. Falconer, classed under the following heads J. Such as arise from bodily orga-nization, namely, sex, temperament, and stature ; 2. Such as proceed from the difference in the time of life ; 3. Time of day ; 4. State of the system respecting rest or activity, viz. sleep, exercise, and mental agitation ; 5. State of the body with regard to temperature ; 6. Effects of food and abstinence : -to these may be added the season of the year, the greater or less pressure of the atmosphere, and a variety of other circumstances, too numerous to be detailed. Thus, the pulse in general beats more quickly in men, especially those of a bilious habit, than in women. In lean persons, whose vessels are large, it is much stronger than in the corpulent or phlegmatic.

Farther, the pulse is more forcible in adults than in children ; but, in the aged, it is slow and hard.— When the atmosphere is close, and productive of rain, as well as during sedentary occupations, the pulse is languid, and perspiration is diminished. In the month of May, it is quick, and sometimes even violent : as the summer advances, the rapidity of circulation, though remaining nearly uniform, is considerably reduced in strength ; so that in autumn it is slow, soft, and weak; but, on the approach of winter, the pulse becomes hard and strong.

The most powerful agents, however, on the human pulse, are the passions and affections of the mind: thus, under the influence of terror, it is unequal, small, and contracted ; under that of joy, it becomes frequent and large ; during anger, it is hard, and beats quickly ; and lastly, in persons pursuing intense study, it is unusually languid.

According to our experience, the standard of a natural pulse in adults, in a good state of health, appears to be 72 in men, and 66 in women ; though Dr. Falconer fixes it, in general, at 75 in a minute, and its extreme acceleration at 1 25. Thus, we observe from his computation exhibited in a table, that, for a person whose natural pulse is 75, the beginning of fever is put down at 96;; hectic fever at 108 ; and inflammatory fever at 120. According to this proportion, in one whose natural pulse is 60, the first or" these stages should be about 77 ; the second, 86 ; the third. 96. On the other hand, a natural pulse of 8.0 would require them to be about 102, 115, and 128.

Independently of other symptoms, neither the frequency of the pulse, nor its peculiar modification, appears to be of so much consequence in diseases, as is generally imagined. Formerly, the urine was chiefly consulted ; but, in modern times, the quacks have usurped that criterion; and physicians of great practice seem to pay particular attention to the pulse ; as their time is equally short and valuable.— See Physician.