one.

In percussing, various methods are employed: one physician preferring one method, another preferring a different Without arrogating to myself superior judgment, I may be permitted to describe my own method first. My method is the mediate one. I make use of the hammer and the pleximeter that nature has kindly provided me,-those which cost nothing, that require no box or case, and that, moreover, cannot be left behind. In a word, I employ the fore and middle finger of the right hand as a hammer, and the fore finger of the left hand as a pleximeter. The first strike the blow, the other receives it. I find the employment of these parts only amply sufficient in most cases. When a very strong blow is to be made use of, the ring finger of the right hand is added to the others.

The finger employed as a pleximeter or blow receiver is laid gently and with a little pressure over the part to be percussed, with the back or hard or bone part looking outward. No air is allowed between the finger or fingers and the chest, otherwise a pseudo cracked-pot or clink sound may be obtained by its expulsion. The finger is laid across a rib, or which is better, in an intercostal space. I find in many cases that the finger fits best applied to the interspace; and I believe that a given blow produces a fuller sound when the finger is placed there than when placed upon the rib. When the intercostal space is depressed either from plastic adhesions or from wasting, it is best to place the finger in it and not across it. Air expulsion sounds are thus avoided.

The finger or fingers employed to give the blow should fall neatly and decidedly upon the middle of the back of the pleximeter finger. A moderate blow is perfectly sufficient in ordinary cases. The hammer fingers need not be raised above the pleximeter finger more than one or two or three inches, before they are made to descend. By confining the separation to this extent, the danger of a side blow being struck, or of missing the finger altogether, is avoided. The fingers should fall at right angles. The arm need scarcely be moved. The hand is moved simply upon the arm. By attending to this and keeping the finger points at the same level, a cleanness of blow, so to speak, is secured, difficult to obtain by great movements of the arm and shoulders.

We should avoid heavy, clumsy blows. I have seen the arm and the shoulder employed in percussion, and the fingers separated from the chest about a foot. Such percussion is inexact, painful to the patient, and conveys an im

pression of awkwardness and unskilfulness that had better be avoided.

Considerable force is occasionally justified when moderate percussion fails to detect a departure from the healthy sound. In deep-seated tubercle rather forcible percussion will sometimes elicit a degree of dulness when this cannot be obtained by light tapping. A strong blow in cases of empyema, and in perforation too, seems to effect a contrast which is not so well secured by gentle percussion. A strong blow is also justifiable if we desire that the character of the percussion sound should be heard by several bystanders.

When the blow is struck upon the finger, this part should be immediately dealt with, so as to avoid constraining pressure, for the production of sound, as I have already often said, is greatly hindered by pressure.

The mode in which the finger acts which serves to receive the blow has been little noticed. The employment of this part is very necessary, for if we attempt to percuss without it or without a pleximeter, we fail much in our efforts. Even if we percuss the soft part of the finger instead of the hard part, the result is greatly inferior. When the naked chest is struck directly, the fleshy parts act so as to prevent that amount of forcible collision sufficient to set the contained parts of the chest into sonorous vibrations. When the hard part of the finger is struck, forcible collision is produced, and this is transmitted to the parts beneath, now rendered more solid by the pressure of the finger. Percussion of the clavicle, as it is little covered with soft parts, does not require a finger to be placed upon it, for the collision between it and the end of the finger is sufficient to throw the parts beneath into sonorous vibrations.

The cracked-pot sound is best elicited by a smart, clean, strong blow. We should aim well, for faulty efforts do not succeed, and by partially emptying the cavity of air, may frustrate other blows, however well delivered.

Hammers have been recommended by various physicians for the purpose of giving the blow. It has been said that greater uniformity of force is thus secured. But I myself have not found the employment of a hammer of much use. In ordinary percussion I infinitely prefer my naked hand and fingers, the movements of which I can regulate fully as well as those of a hammer. Besides, I obtain the benefit of the perception of chest resistance. The hammer strikes a pleximeter, for the most part a disc of ivory or indiarubber. The hammer is usually formed of steel, and is about four inches in length. The part

HAMMER AND PLEXIMETERS.

311

which comes in contact with the pleximeter is tipped with a point of indiarubber. There are some occasions on which such an instrument may be useful,-when a heavy blow is required, which, however, must be rare; when it is necessary

Hammer.

to elicit loud sounds, as in teaching students; or when the arms and hand of the percussor are feeble. Dr. Theophilus Thompson, I believe, had a very healthy view of the value of the hammer. When that physician lost much of the muscular power of the hand and arm, he proposed to bring this instrument to his aid in percussion, as he himself informed me. I fear his death soon after prevented him or his patients benefiting by his proposal. The hammer is much employed upon the continent. Dr. Hughes Bennett employs it, and probably his success in procuring the cracked-pot sound is connected with this fact.

Pleximeters, or substitutes for the blow-receiving finger, have been recommended. That of Piorry, the inventor of this aid, is made of ivory, being a thin oval disc, an inch and a half long, and about three quarters of an inch wide at its widest part.

Piorry's Pleximeter.

Some pleximeters have been formed of indiarubber. I have employed these instruments, but I have abandoned them in ordinary percussion. I found that they produced sounds of themselves rather than of the chest. They fitted ill in wasted patients. I have found air confined under them, and again this has been expelled with a noise often clinking during percussion. They are greatly inferior to

the finger in respect of the sense of resistance, and of nice ready management. When the hammer is employed, the pleximeter is essential. The pleximeter is to be placed in or over an intercostal space, or upon a flat surface, and fitted well with gentle pressure upon the body, and held by the thumb and forefinger of the left hand. It may be employed together with a hammer or with the fingers. The blow is struck at the middle.

An instrument combining both a pleximeter and a hammer was contrived by Dr. Aldis some years ago. It consists of a hammer moving on a fulcrum, and of a disc of cork which receives the blow of the hammer. The cork disc is placed upon the chest, and the hammer is raised by the finger to the required height. The higher the hammer is raised, the more force is obtained. The hammer falls by the operation of a spring. Great uniformity of blow is obtained by this instrument. This ingenious contrivance has obtained the name of echometer. I have made use of the original instrument, kindly lent to me by its author. While the sound obtained by the echometer varies sensibly with the resonant quality of the chest, I must confess that the sound of the instrument itself has perplexed me, and I have missed that fine adjustment and appreciation of the blow, and of the resistance, and also the power of immediately suspending

R

Dr. Aldis's Echometer.

pressure which I enjoy in simply using the unaided fingers. Besides, the force cannot be greatly varied as when the fingers are employed, and I have, in using the echometer, soon found my hand to become fatigued. It may, however, be useful in teaching percussion to a class.

DR. SIBSON'S PLEXIMETER.— Dr. Sibson has more recently contrived an instrument of a similar character. Dr. Sibson's pleximeter consists of a plate of ivory which receives the blow, and of a brass hammer or weight working in a metal frame. The weight or hammer is raised by the fingers; these being removed, the weight or hammer falls upon the ivory plate by the elasticity of an indiarubber band connecting the weight or hammer with the ivory plate. The hammer works perpendicularly to the plate. I have carefully experimented with this instrument, and I must admit it to be a

superior and valuable instrument. The working of this instrument is easy, the hand does not become tired, it is little formidable in aspect to the patient, it is not expensive, and the force can be nicely varied. The different degrees of resonance are well marked by this interesting and pretty instrument. If we percuss the crown of a hat, a different note is obtained by any move of one quarter of an inch from the centre towards the edge. The degrees of resonance are also well made out upon the phthisical chest. Perhaps for a physician not yet able to make uniform strokes with his fingers, this instrument would be useful. But I must confess, that in infinite variation of force, and in rapidity and nicety of percussion, the fingers of the practised percussor are greatly superior.

Dr. Sibson's Pleximeter.

CHAP. XLII.

INSTRUMENTS.

Auscultation.-Immediate.-Mediate.-Laennec's Stethoscope.-Solid and hollow Stethoscopes.-Materials for Stethoscopes.-Construction.-Application. -Extraneous Sounds.

AUSCULTATION. After having obtained every reasonable information from the practice of percussion, the patient suspected of pulmonary consumption is now to be submitted to the test of auscultation. In every stage of the disease, this test reveals facts of the highest importance; it is the most valuable one which we possess, but it is in the first stage of the disease that auscultation exceeds most in importance all other modes of investigation. We obtain much light, direction and suggestion, from the coarse, deficient inspiratory sound, and the coarse prolonged sound of expiration in the first stage. The moist crackling of the second stage is most significant. The cavernous blowing in and out, the cavernous voice, and the cavernous gurgling, speak with force of most serious disruption in the third stage. The amphoric blowing, the amphoric diffused vault-like voice, and the metallic tinkle convey truths to the mind at once of the