blowing sound corresponding to the beat of the heart being systolic, and the one between the beats of the heart, diastolic. A murmur once established is not always equally perceptible, sometimes becoming very faint, or disappearing entirely by the change in position on the part of the applicant; and sometimes is only manifest when the heart is acting forcibly. Posture exercises a very decided effect on murmurs. The blowing sound is distinct in a recumbent posture, becoming very faint, or disappearing entirely, when the applicant stands erect; or the reverse is the case.

A source of error is the resemblance between the natural respiratory sounds of the lungs and the blowing sounds of the heart, but a distinction may be readily made when the applicant suspends breathing. To determine the seat of a murmur, we must ascertain the point of its greatest intensity. The murmur produced at the mitral orifice is heard most distinctly at, or near the apex of the heart; if generated in the right ventricle or at the tricuspid opening, it is heard immediately above the ensiform cartilage; if developed at the origin of the aorta, it is heard most plainly at the sternum, somewhat toward its left border, on a level with the third intercostal space or the fourth rib, and with nearly equal distinctness over the second costal cartilage on the right side. The pulmonary artery is not often the seat of a murmur, but when it is, it is clearly perceptible in the second intercostal space on the right side, and extends to the junction of the third left cartil age with the sternum.

It is very important to examine each portion of the heart separately, since the sounds of valvular disease may coexist in the greater portion of the heart, but the greater intensity of the sounds of one portion of the valves may obscure the location of the others. When satisfied as to the seat of a murmur, we naturally turn to inquire into its origin, and there is nothing in the murmur itself which will tell us positively whether it is caused by an alteration of the fluids or connected with any appreciable change in the structure of the heart. As a rule, a harsh murmur results from organic disease, and a soft murmur from functional disease, but there are many exceptions, and we can judge with more certainty from the time of the blowing sound. A murmur attending distention of the heart indicates injury of the orifices; while a murmur occurring during the contraction may indicate simply a change in the state of the blood and in the force and velocity with which it is circulating; but in the latter case, the abnormal sound is temporary and disappears with the excitement. When arising from an impoverished state of the blood, it is generally soft, of low pitch, accompanied with a humming sound in the veins of the neck, and is present over the base of the heart.

It is a great mistake to suppose that every murmur heard over arteries is connected with disease of the heart, as it is frequently from impoverished blood, and it is even stated that pressure of a healthy heart may generate a murmur. To describe more in detail the murmurs of the interior of the

heart, the elements of quality and intensity hold a subordinate place, for the same murmur at different times may be grating, rubbing, blowing or muscular in character, without its significance being altered by any of these changes in quality.

The precise pathological significance of endocardial murmurs is appar ent from the following table, taken from Loomis :

The sounds which originate on the outside of the heart, or pericardial murmurs, result from irregularities of the surfaces of the pericardium; the smooth, serous covering of the heart, while roughened by deposit of any kind, gives rise during movement to a sound which may be single, but is more usually double, and in character is very variable; it may be a distinct to and fro rubbing murmur, or may be scratching, grating or whistling, but has one quality which is constant and diagnostic, although it is often difficult in spite of this to distinguish the friction. The sound, too, is apt to mask the sounds of the heart, and it is not at all times, although heard over the cardiac region, due to inflammation of the pericardium, for the exudation may be on the surface of the pleura adjacent to the pericardium, and the murmur be caused solely by the movements of the heart; and, again, the sound heard in the pericardial region is in reality the rubbing of an inflamed pleura; but in this case, if the person suspends breathing, the pleural sounds cease. There are also some sounds produced by the action. of the heart, which are neither cardial nor pericardial; these sounds are mostly systolic and inspiratory, and usually cease with cessation of the respiratory movements.

EXAMINATION OF THE PULSE.

TH

THE PULSE.

HE pulse, when felt by the tips of the fingers at the wrist, or elsew here, registers the change in the fullness or distention of the artery, as the blood is forced through the systemic circulation by the contraction of the heart. The best way to measure this fullness, or tension of the pulse, is to compress the artery with the index finger, while the two adjoining finger tips placed more distant from the heart, register the amount of pressure necessary to stop the flow of blood.

THE SPHYGMOGRAPH is an instrument which registers the various qualities of the pulse by means of tracings on a diagram. From an analysis of these we perceive, that what may appear simple to the sense of touch, is really a complicated phenomenon, requiring careful study.

PULSE TRACINGS.-The sphygmograph demonstrates that the movement of the artery is a compound of three waves, called the summit wave, the tidal wave and the dicrotism.

The summit wave, which caps the line of ascent of the trace, is due to the sudden vibration in the blood column, immediately following the lifting of the aortic valves by the discharge of blood from the left ventricle.

The tidal, impletion, or small secondary wave, is due to the distention. of the arteries, following the increased pressure in the aorta and great arteries from the sudden influx of the ventricular contents.

The dicrotism, or great secondary wave, is an oscillation of the current of blood in the arteries, mainly produced by the recoil of the blood column from the quick closure of the aortic valves.

TYPICAL PULSE TRACING.-(See fig. 1.) A pulse trace consists in a line of ascent, a to b, ending in the summit wave b, and corresponding with the first part of the ventricular systole. From the summit wave the line falls until it is again raised by the tidal wave, due to the impletion of the vessel. After the tidal wave, a more marked descent occurs, called the aortic notch e, and the line again raises into the dicrotic wave d.

The line of descent from b to a' is then broken by two waves and two notches. The two waves have been described; of the two notches, one precedes the tidal wave and indicates a slight collapse in the arterial wall after the oscillation, called the summit wave; while the other, called the

aortic notch, precedes the dicrotic wave, and marks the fall in pressure on the arteries antecedent to the closure of the aortic valves.

Fig. 1.-Typical pulse trace: a to b, line of ascent; b to a', line of descent; ¿, summit wave; c, tidal wave; d, dicrotic wave, or dicrotism; e, aortic notch.

The instant the aortic valves close, the line is interrupted again. It is the bottom of this aortic notch, marking the closure of the aortic valves, which indicates the end of the ventricular systole. The rest of the line of descent corresponds with the diastole of the ventricle.

MODIFIED PULSE TRACINGS.-The pulse trace is modified by the state of arterial fullness, or tension.

High tension is denoted thus-The line of ascent is less lofty; the tidal wave is large and often blended with the summit wave; the aortic notch is shallow; the dicrotism not much developed, and the line of descent is more gradual.

Low tension. The line of ascent is lofty; the summit wave distinct; tidal wave small; the aortic notch deep; the dicrotism highly developed, and the line of descent sudden.

In arterial degenerations, when the normal elasticity of the arteries is lost, these modifications are interfered with.

The rate, rhythm and force of the pulse depend upon the heart. The art of feeling the pulse consists in discovering, through the sensa tion of feeling, the condition of the heart, arteries and blood.

A hard, cord-like artery indicates degeneration or senile changes. FREQUENCY OF THE PULSE depends on the rate of the cardiac contractions. This rate varies with age, position of the body, sex, stature and other physical or psychical influences. In the newly born infant the pulse beats from 130 to 140 per minute, but the rate gradually falls, until after the sixth year it is under 100. Up to the age of maturity, there is a further decrease of thirty beats to about seventy per minute. In old age the rate often rises slightly.

Postures. The pulse is slowest in the recumbent position; sitting, it is five beats faster and standing, it is ten beats faster in the male and seven in the female.

Sex. The female of seven years has about ten pulse-beats a minute more than a male of the same age.

Stature. Persons six feet in height have a pulse three or four beats slower than men five and one-half feet high.

NORMAL PULSE-BEATS PER MINUTE.

Increased frequency in health is occasioned by any kind of exercise; mental emotion or nervous excitement; a full meal; it is higher in the evening than in the morning; when awake than asleep. In disease a quick pulse may be one of its first indications, as in fevers, debility, chronic valvular affections of the heart, nervous disorders, intemperance, etc.

The jerky pulse is a hurried beat followed by an abrupt stop, and indi cates defect in the aortic valves, or some nervous affection. The waterhammer pulse denotes aortic regurgitation.

It is seen in some

Diminished frequency of pulse rate is not common. of the blood diseases, jaundice, anæmia, diabetes, convalescence from pneumonia, in relapsing fever, fatty degeneration of the heart, in some nervous affections, especially of the medulla oblongata, wherein it has fallen to about twenty beats per minute; in tumors pressing on the aorta or arteries; in diseases of a depressing nature.

RHYTHM OF THE PULSE.-Depends on the action of the heart. Variations are of two kinds, intermittence and irregularity.

THE INTERMITTENT PULSE means the omission of a beat occasionally. Intermittences may occur regularly, say every twentieth beat, or irregularly, and are met with more frequently among the old than the young, in some cases being unassociated with organic diseases.

Causes. It may be caused, temporarily, by nervous excitement; in other cases, by hypochondriasis, dyspepsia, excessive use of tobacco or narcotics and stimulants, gout, over-work, fatty degeneration of the heart, or some cardiac neuroses. It may be the first symptom of oncoming malignant disease. In some persons, especially the old, it is habitual, though they are otherwise healthy.

THE IRREGULAR PULSE presents itself in two forms-irregularity in frequency and irregularity in force, or inequality. The two are frequently