ACOUSTICS APPLIED TO THE HUMAN CHEST 
IN PHYSICAL DIAGNOSIS. 
BY 
J. R. BEAMING, M.D., 
OF NEW YORK. 
Reprinted from the New York Medical Journal, January 26, 1889, and Transactions of the 
New York State Medical Society, February, 1889. ACOUSTICS APPLIED TO THE HUMAN CHEST 
IN PHYSICAL DIAGNOSIS. 
BY 
J. R. REAMING, 3I.D., 
OF NEW YORK. 
Reprinted from the New York Medical Journal, January 26, 1889, and Transactions of the 
New York State Medical Society, February, 1889. 
PHILADELPHIA: 
WM. J. DORNAN, PRINTER. 
1 889. ACOUSTICS APPLIED TO THE HUMAN CHEST IN 
PHYSICAL DIAGNOSIS. 
By J. R. BEAMING, M.D. 
The interior conditions of that marvellous instrument, the eye, are 
made known to us with mathematical precision by the application of 
the laws of light-optics. Any writer or teacher who should reject 
or neglect to apply these laws in considering the problems of vision 
would be unscientific and most likely wrong. In fact, since the appli- 
cation of the laws of light to the study of the eye, ophthalmology has 
become, in the hands of its devoted and learned professors, the one 
branch of medicine entitled to the distinction of being scientific, and 
consequently certain. 
Optics and acoustics are twin-sister sciences, cognate in origin. 
The laws of one, which are familiar, have ever been used in elucida- 
tion of the obscure in the other. 
Yet, while optics has been successfully applied in the diagnosis of 
diseases of the eye, acoustics has hardly been thought of as a surely 
scientific solution of the important and difficult problems of diagnosis 
of diseases of the chest. 
The reason for this is, no doubt, the fact that acoustics has until 
lately been an unapplied science. Its phenomena in nature have been 
subjects of wonder and superstition, rather than for education. The 
ancients placed them all under the dominion of Pan, the mysterious 
god both of noise and of silence, the unexplainable, the source of 
sudden fears and panics. 
Bacon, the great author of modern philosophy, took the greatest 
interest in studying echoes, which he never comprehended as mathe- 
matical results of natural phenomena in such a way as to make 
them practical, as he would have done had he been acquainted 
more fully with the laws of sound. Laennec, who discovered the 
means of diagnosis by auscultation with the stethoscope, and Louis, 
who did so much to establish its use and to make it practical, were not 
learned in acoustics. Therefore it has been said that acoustics is not 4 
BEAMING, 
necessary to any one in order that he may become a good auscultalor. 
The brilliancy of the discovery of Laennec blinded the eyes of the 
profession to its great possibilities then and since, so that auscultation 
has just missed perfection by not being based upon eternal law. 
Laennec stumbled upon acoustic facts when he placed one end of a 
roll of paper against a patient's back and applied his ear to the other. 
Had he been acquainted with the laws of sound, what a grand opening 
would this have been for the establishment of fact, instead of ingenious 
theory, in explaining the laws of physical diagnosis! I would not take 
one leaf from the laurel crown which he so richly won; but rather 
would add to it that which belongs to discovery-its scientific explana- 
tion. Skoda made one more step toward this consummation when he 
discovered the principle of consonation. That was one more discovery 
which again pointed out the fact that all auscultation to be most valu- 
able must be based upon the laws of sound, but went no further; the 
time was not yet. 
But in this practical age of the application of the laws of sound to 
the telegraph, the telephone, the phonograph, and the microphone, it 
becomes an easy thing to apply acoustic law to the diagnosis of diseases 
of the chest, which will raise this branch of medicine also from the 
realm of hypothesis and place it upon a level with ophthalmology. 
Mr. Edison, the discoverer of the phonograph, while listening to music 
and holding his hat in his hand, noticed that the crown vibrated sen- 
sibly to the sound, and this suggested the instrument. For, if vibra- 
tions in the air-waves could cause this diaphragm to vibrate, why should 
not vibration in a diaphragm also send sound-waves into the air; these 
waves, recorded in some penetrable substance by a point, will, on going 
ovei' the same ground again with the point, reproduce the sound ; and 
thus the discovery was made. 
The discovery of the phonograph began and ended with two elements 
of acoustics -primary vibrations and secondary sound-waves. All 
sounds originate in vibrations which pass through the universal 
medium, the air, in waves the same as does light. The rapidity of the 
vibrations constitutes pitch, and is limited in recognition by the ordi- 
nary human ear, practically, between thirty-two and forty thousand in 
a second. Less than thirty-two vibrations in a second give the idea of 
distinct sounds, and more than about forty thousand in a second result 
in silence, too rapid to be taken notice of by the sense of hearing. 
Tyndall says that if the vibrations number less than sixteen a 
second we are conscious only of the separate shocks. If they exceed 
thirty-eight thousand a second, the consciousness of sound ceases alto- ACOUSTICS OF THE HUMAN CHEST. 
5 
gether. The range of the best ear covers about eleven octaves, but an 
auditory range limited to six or seven octaves is not uncommon. 
Music embraces seven octaves. 
Thunder is, in nature, the lowest note which can be heard as con- 
tinuous sound, and the squeak of an insect the highest in pitch; but it 
is possible that there are still higher notes of the insect which we do 
not hear, from their too great rapidity of vibration failing to send out 
sound-waves that could make an impression upon the tympanum. 
These are fundamental principles in acoustics, and are essential in 
understanding the physical conditions of the chest, as we shall see 
whenever we make application of these laws in diagnosis. 
The chest-chamber is encompassed by walls lined internally with a 
dense, elastic, smooth membrane-the costal pleura. The walls them- 
selves are formed of the ribs, bone, and cartilage, which are connected 
by thin muscles which interlace, allowing a very considerable move- 
ment ; but, whether contracted or distended, they are curved in such 
a way as ever to present a smooth reflecting surface covered by 
the pleura. This chamber has slight movement in the superior part, 
where there is but little cartilage, but expands largely at the base, 
where cartilages are attached to the ribs, lengthening them in front 
and attaching them to the sternum, which is itself composed of several 
pieces attached to each other by cartilage, in order to permit move- 
ment, and all are closed in at the base by a diaphragm of muscle with 
great power of expansion and contraction, so that while ever continu- 
ing a perfect acoustic chamber in mathematical form, it may be 
enlarged or contracted, and consequently its power augmented or 
diminished with the speed of thought. The upper and unyielding part 
of this chamber is in the form of a cone; above it, in the trachea, 
which passes down through it, is placed the larynx or sound-box, 
where voice vibrations are primarily formed and conducted in tubes in 
every direction to the chest-wall, where they are reflected again and 
consonated into a mass of harmonious sound, and, coming back, are 
emitted through the larynx and mouth into the open air, setting it 
into vibrations of speech or music for the exquisite enjoyment of all 
within hearing. The acoustic chamber of the chest in health is a per- 
fect instrument for the formation and reflection of sound-waves, and it 
has been said that the violin, the most perfect instrument of music, was 
formed upon its model. As a sound-chamber it is indeed perfect, but 
it is liable to be altered in shape and its acoustic perfection destroyed 
by changes of form from intrapleural adhesions, pressure of tumors, or 
diseases of the spine, etc. Also, the chamber is filled with the lungs and 6 
BEAMING, 
heart and their appendages. All of these interfere with the formation 
of sound and its passage in waves and reflection from the surfaces of 
the anterior walls. But the lungs are an independent acoustic instru- 
ment, formed of tubes and sacs, for the passage of air and the aeration 
of the blood of the body, which is brought here and is spread out and 
exposed in the pulmonary capillaries by the heart and bloodvessels; 
so that the contents of the chest are of the utmost importance to the 
breathing, living, pulsating being. The membranes, in which the 
capillaries are spread out, are in sacs and minute tubes filled with 
alveoli, thin, diaphanous, and distensible to a wonderful degree, and yet 
contract upon the contained air with active force in alternate move- 
ments in which the air itself is a factor. Constantly renewed by in- 
halations about sixteen times a minute, or once every three or four 
seconds, the fresh, cool, pure air is mixed with warm, impure air, and 
vital interchanges at once commence. The fresh air expands with heat 
and gives up its oxygen to the greedy blood, and receives in exchange 
the worn-out material, carbonic and nitrogenic, as filth to be thrown out 
of the living organism in expiration, while the cooled, freshened, puri- 
fied blood goes on to the heart to be sent through the systemic circula- 
tion, to continue the growth and nutrition of the body. 
During this vital act of one respiration in the time of three or four 
seconds, the heart-a double pump-sends half an ounce of blood 
about twelve times in each direction: the right to the lungs, venous 
blood ; the left, arterial blood, to the system. These movements of the 
lungs and the heart are rhythmic, and are accomplished with sound- 
the heart-beat and respiratory murmurs, contemporaneously. The 
auscultator must take in both, and give each its due importance, recog- 
nizing at the same time that they occur in an acoustic chamber, and 
are reflected from its walls, consonated, harmonized, and governed by 
definite law, and then we will appreciate auscultation as scientific. 
Each little sac is a resonator, distended by air constantly rarefied by 
heat, upon which it actively contracts, causing vibrations which help 
to make up the true respiratory murmur. Each sac is connected with 
a bronchus, and in this way with the outside air at each inspiration 
and expiration, and consequently sound-waves in the open air pass in 
and are consonated in each sac, as are also the friction-vibrations of 
the tidal air pushing in and out through the open bronchi. There are, 
therefore, three sources of vibrations going to make up the true respira- 
tory murmur, and each one can be distinguished by the organ of hear- 
ing placed in audible connection with the chest-wall. Nor does the 
fact that the chamber, or its contained system of tubes and consonating ACOUSTICS OF THE HUMAN CHEST. 
7 
sacs, may have lost much of their acoustic perfection make it any the 
less necessary to apply these laws in order to make a correct diagnosis 
of the location, extent, and condition of the injured part. On the con- 
trary, it increases the necessity, for by the application of these law's we 
measure the deficiency in the only scientific way. 
The lungs may originate sound-vibrations in the air-sacs when in 
perfect condition only - that is, only when the walls of the sacs 
contract upon the contained air causing muscular sound-vibrations, 
called muscular susurrus, which is consonated in the compressed air of 
the sacs into a body of sound. 
They may also receive vibrations from without, or from friction of 
the moving air within the tidal space of the convective system-that 
is, within the space from the entrance at the mouth and nose into the 
bronchi, as far as there are developed cartilaginous rings to keep them 
patent, or until about the fourth division. Here the tidal air meets 
the residual air and immediately becomes a part of it, or in so short a 
time as to be practically immediate, by the law of the diffusion of 
gases, but which is evidently assisted by the contraction of the disten- 
sible bronchi, without cartilage, within the true respiratory system. 
The tidal-air space, where the bronchial tubes have cartilaginous rings 
to keep them open, is the location of friction-sound-the air moving in 
and out-and this friction-sound, as well as sound-waves in the open 
air, are consonated in the air-sacs. 
The distance between the tidal-air space and the air-sacs is filled 
with compressed air, confined in distensible tubes in connection with 
the air-sacs, and together they form the true respiratory system. These 
tubes do not originate sound ; the residual air does not cause friction. 
The vibrations from without and the friction in the tidal-air space are 
not consonated in them, but pass through them silently as the sound 
in a speaking-tube. It is spoken at one end of the tube and heard at 
the other, but not along the course of the tube, for the sound-vibrations 
are only at the ends. This is an acoustic law' of importance in diag- 
nosticating diseases of the lungs, for where unusual sounds or noises 
come from the true respiratory system other than acoustic consonations, 
or the muscular susurrus of the sacs, it is an evidence of disease, and 
is caused by conduction by pathological products. Conduction then 
becomes an acoustic fact of warning; pathological changes have taken 
place. 
The heart, also within the chest acoustic chamber, originates sound; 
it also obstructs sound, and at the same time conducts sound, which 
seems paradoxical, but is true. Its particular and useful office is to 8 
LEAMING, 
pump the blood into the great arteries and through their many divis- 
ions until it comes within the influence of attraction by affinity-that 
is, the aerated blood is sent from the left heart with force commensurate 
with its purpose, and is assisted by the great arteries following in con- 
traction sending the blood on until it is near enough to come under the 
influence of the attraction tissues eagerly waiting for the coming 
nutrition. 
Without this attraction between the blood and the tissues the circu- 
lation could not go on. The physical force of the engine-the heart 
and arteries-sends it but a certain distance; affinitive attraction does 
the rest. A power sufficient to send the blood through the capillaries 
would destroy them. So the forces are divided. The heart, the arteries, 
and the capillaries act in unison, and their harmony is evidence of 
health ; their want of harmony, of disease. The right heart beats ex- 
actly in the same time as the left. In fact, they have the same beat. 
In sounds and rhythm the right, like the left heart, has three sources 
of force-the heart, the arteries, and the capillaries in the true respira- 
tory system. There is this slight difference; the right heart is a little 
weaker, the arteries are not so strong nor are the capillaries as vigorous. 
This is, no doubt, owing to the fact that the circulation itself is shorter 
and less force is necessary to complete the circuit, and because of the 
active affinitive attraction between the air and the blood, and because 
both are free to move toward each other. Both hearts are indeed but 
one engine. One power moves both in the same moment of time; 
there is no such thing as heterosynchronous action. Harvey noticed 
in his study of the incubation of the hen's egg, that the first appearance 
of movement in the germinal spot after about two days was a red point 
which appeared and disappeared rhythmically. This is the first evi- 
dence of organic life, or life of the body, and this rhythmic movement 
commences before there is any heart, or even a rudimentary pulsating 
tube, which answers in the lowest forms of animals for a heart. The 
rhythmic movement is sui generis. It is the one characteristic, 
manifest action of organic life in man as well as in animals of a lower 
order. Rhythmic movement is primary evidence of a commencing 
independent existence, here it builds its home; first, the simple pulsating 
tube, which becomes an auricle, and then a ventricle is added, and 
then in time another auricle and another ventricle, and becomes a 
double heart, and the arteries are pushed out until finally there is a 
perfect body-two circulations, a digestive apparatus, a brain and ner- 
vous system-a man. But still the rhythmic pulsations of the heart ACOUSTICS OF THE HUMAN CHEST. 
9 
go on counting time until the last one, when life ceases and decay 
begins-the cycle of human life. 
The heart's sounds may be brought into the chest-wall at two different 
points, from or by either heart, by conduction, and thus give the idea 
of duplication; but the application of acoustic law corrects the illusion. 
In the human chest the heart lies, or is hung, in the middle, ob- 
liquely, the apex pointing to the interspace between the fifth and sixth 
ribs, while the base extends to the right upward and backward, and it 
is partly in the right and partly in the left chest. It is attached to the 
mediastinum and to the root of the lungs, and is capable of considera- 
ble movement up and down and laterally, outside of the rhythmical 
beat. It is inclosed in a sac, arising from the bloodvessels, lined upon 
the inside and covered upon the outside with serous membrane-the 
pericardium. This sac lies naturally in intimate connection with the 
heart, conducting sounds perfectly, without adhesion or pathological 
attachments. 
The lungs, separated in the middle by the mediastinum, fill the chest 
with the exception of the heart, which has a space hollowed out in 
them for it, only leaving a triangular space in front uncovered-the 
apex-beat area, where it comes against the chest-wall, and into which is 
delivered its sound directly, nothing intervening but the close-fitting 
pericardial sacs. 
This, perhaps, tedious description of what you learned so carefully 
in your student days is only given to remind you how entirely it all 
agrees with the laws of sound. The lungs press against the inner chest- 
wall during full inspiration in every space except that of the apex-beat 
area, which is occupied exclusively by the heart in health. The lungs 
convey sound through their convective tubes and deliver it into the 
chest-wall through the air-sacs with diminished intensity during expira- 
tion and with increased intensity in inspiration. The lungs are a per- 
fect conductor of sound in the direction of their columns of air in tubes, 
but are non-conductive in any other direction. The lungs shut off all 
sound coming from the heart, except by natural direct conduction 
through the mediastinum, in all parts covered by them; so that when- 
ever the heart-sounds are heard otherwise through the lung-substance 
it is acoustic evidence of pathological change. Either the lung is con- 
densed by pressure, or there is consolidation or adhesions. The heart 
delivers its sounds only by indirect conduction through the mediastinum 
to diagnostic points in and near the sternum ; buf directly, into the 
apex-beat area, with diminished intensity during the diastole and in- 
creased during the systole, because it is then pressed against the chest- 10 
LEA MING, 
wall. Of course, the heart shuts off all respiratory murmurs within the 
apex-beat area. It conducts sound when pressed against the chest-wall, 
or when there is consolidation of the lung, or adhesions attaching the 
pericardial sac to the lungs and the lungs to the chest-wall. 
As said before, the heart is a double pumping-engine, its stimulus of 
contraction and repose being fundamental in the organic life of the 
body. The rhythmical heart-beat, commencing before the heart had 
structure or form, still marks the time of the individual life-seventy 
to eighty beats per minute ordinarily, sometimes slower and sometimes 
faster-as if nature had originally intended it should be sixty per 
minute, and something had disarranged its beat. But any notable 
change has come to be a sign of danger. 
The heart is a hollow muscle divided into two chambers and united 
by a common wall-the septum ventriculorum-and during the closure 
of the auriculo-ventricular valves each side is again divided into auricle 
and ventricle. When the heart is at rest there are two chambers; dur- 
ing contraction there are four. The blood enters the heart on either 
side through the auricles during the heart's rest after contraction, 
passively distending it, and floating the auriculo-ventricular valves up 
to their proper place, dividing each heart into two chambers, with doors 
not quite closed, when the motion of contraction, commencing in the 
auricles, instantly passes into the ventricles, closing tightly the auriculo- 
ventricular valves and forcing the contents of the ventricle into the 
open aorta and pulmonary artery. Then follows muscular relaxation. 
The resiliency of the aorta and pulmonary artery, reacting, brings 
back the blood with force and closes the semilunar valves, and holds 
them until they are again forced open by the blood, which is again 
forced into the artery and throws the valves back against their walls 
for its easy passage. 
The heart works and rests, contracts and relaxes. Auricle and ven- 
tricle in action are one. And were it not for the closure of the semi- 
lunar valves forcibly by the return shock of blood in the arteries, there 
would be no mystery in the sounds and intervals of silence in the 
cardiac cycle. It would simply be contraction and relaxation-one 
sound and one interval of silence. But the return blood, closing the 
semilunar valves, makes another sound and divides the interval of silence 
into two parts, one short and the other long, and thus we get the 
rhythm of the cardiac cycle. The first sound is long, formed entirely 
by the heart's contraction, occupying about one-third of the cycle, 
and is emphasized by the apex-beat; the interval from the apex-beat 
until the "tack" sound of the closure of the semilunar valves is the first ACOUSTICS OF THE HUMAN CHEST. 
11 
interval of silence, short. And this gives us the rhythm; first sound 
long, first interval of silence short, second sound short, a mere " tack," 
and then follows the long interval of silence, filling up the cycle. 
The study of the heart's rhythm is entirely acoustic, and its right 
apprehension is of far more importance than all the other signs together, 
for there can be no alteration of the rhythm without pathological 
cause. Murmurs may be heard, and in various areas, and mean little 
or nothing if the rhythm remains correct, but the slightest variation 
in rhythm means possible danger. 
The closure of the valves causes the second sound, and divides the 
interval of silence. 
As to the mechanism of the first sound there are different opinions. 
More than twenty years ago, before the County Medical Society of 
New York, I gave a synopsis of the views held by the profession of 
that time, and presented iny own, which I then believed agreed w7ith 
acoustic law and physics. I feel more sure now than then even that I 
gave the true philosophical explanation. It is this: The mitral valve 
(and the tricuspid) are curtains closing the auriculo-ventricular open- 
ings. They are floated up to their plane by the inwelling blood during 
the relaxation of the heart, and are held by tendinous cords attached 
to the valves and to the fleshy walls of the ventricle through the inter- 
vention of fleshy columns or the small muscular elevations arising from 
the interior walls. These tendinous cords hold the curtains of the 
valve and prevent them from being forced through the opening. They 
are strong, take up but little space, and offer a minimum obstruction to 
the rushing blood. The valve, the ventricle, the columnae carneae and 
the musculi papillares contract in such a nice way that the curtainsof 
the valves are kept in exact coaptation and resist the forcing blood and 
turn its stream into the course of the natural exit. When every drop 
of blood has thus been forced out of the ventricle the heart relaxes and 
the semilunar valves are closed. To repeat: The curtains of the valves 
are floated up to the closure of the auriculo-ventricular system, without 
force, for as yet there is no contraction-then, like a flash of lightning, 
the contraction commences in the auricle, instantly passes down into 
the ventricle, and the valves are forcibly closed. Of course, there will 
be sound. The stretched and vibrating membrane of the valve gives a 
drum-like sound of low note; the chordae tendineae are also thrown 
into vibrations in harmony with the valve, but of higher pitch. 
As the contraction of the heart goes on, the valve-note grows less 
and less and the higher note of the chordae increases until the apex 
strikes the chest-wTall and relaxation commences. This is the mechanism 12 
BEAMING, 
of the first sound. It begins in a low note, and gradually increases in 
pitch until apex-beat. As the whole cycle is about only one second, 
the time of the first sound is not more than one-third of a second-a 
very short time in which to make observations of a complicated con- 
traction of a hollow muscle, which suddenly begins to contract upon 
its contained blood and to expel it from its suddenly formed, bound, 
girded compartment, rapidly contracting in size until it has ejected all 
within and the apex is brought against the chest-wall with force. Then 
as suddenly relaxing, every muscular fibre, the chordae, and valves 
lying loosely and without force in the midst of the greater chamber, 
which fills passively with blood, floating the valves into place for the 
artificial division when the contraction again binds, girds, and holds 
the compartment, while it systematically contracts in size, expelling its 
contents. All of this is done with accompanying sound-first of the 
valve, then of the valve and vibrating cords, and lastly of the cords 
alone, and is ended by the stroke against the chest-wall, all in one- 
third of a second, to be commenced again after two-thirds of a second 
of relaxation, divided into two unequal parts by closure of the exit 
valves and the second sound. 
The heart does but one thing: it contracts. The relaxation is pas- 
sive. Whatever else takes place is outside. The muscular susurrus, 
however, of the heart-muscle is a physical fact; also the blood friction 
rushing through and among the chord® and against the tense vibrating 
valve, which has suddenly divided the right or left heart into two com- 
partments-auricle and ventricle. 
The auscultator will become learned in the rhythm of the heart's 
cycle, the quality of its sounds, and the length cf its intervals of 
silence. Like the engineer with his engine, or the clock-maker with 
his time-piece, he becomes intimate with its sounds or murmurs, and 
they constantly communicate with him in a most intelligent manner. 
If the engineer is asleep and the rhythm of his engine is disturbed, he 
instantly awakens. The clock-maker of old used a stick of wood be- 
tween his ear and the clock to listen long before Laennec was born, 
and he could detect any change in the regular movement of the works 
or the tick at once. 
The first sound, then, is formed by the vibrations of the tense mitral 
valve, by the tense chord®, the sound of muscular contraction, and the 
friction of the blood. If it loses the valve sound-the low, drum-like 
note-we know that the vibrating power of the valve is affected. If 
it has also lost the higher note of the vibrating chord®, we know that 
they are affected pathologically. If the valve and chord® sounds are ACOUSTICS OF THE HUMAN CHEST. 
13 
both gone, then all that is left of the first sound is of blood friction 
and muscular contraction. If the first sound is increased in energy, 
and the first interval of silence in length, and the second sound is 
emphasized with the second interval of silence shortened, we know 
that there is obstruction at the aortic orifice, or regurgitation, and there 
will be arterial tension. But regurgitation is practically obstruction, 
and must soon cause hypertrophy; but hypertrophy is compensation. 
When compensation is sufficient, arterial tension will have subsided. 
In our description of acoustic facts we now come to the organ of 
hearing in the ausculator, in which we will content ourselves by de- 
scribing it as inclosed within the temporal bone of the skull, with 
entrance to it from without by a curved foramen across which is 
stretched a membrane-the tympanum-which receives the waves of 
sound, registers them, and communicates them to an interior mechanism 
of curious and scientific construction, the description of which we will 
not now indulge ourselves in. The tympanum is supplied with small 
muscles and bones, which act as machinery to make it tense or relaxed 
as may be necessary for its acoustic purpose. There is also an entrance 
for air to the opposite side of the tympanum of great importance to its 
usefulness. 
The methods of auscultation are by placing the ear against the 
chest-wall so that the drum may receive the vibrations; or by a piece 
of wood or other sonorous substance placed one end against the external 
ear and the other against the part to be auscultated ; or a tube may 
enter the external meatus or opening to direct the sound-waves against 
the drum. The binaural stethoscope of Cammann, conveying twin 
waves to either drum, is, in mechanism, the most perfect instrument 
for artificial auscultation invented. But, while stethoscopes have par- 
ticular advantages and claims for use as a means of avoiding filth and 
vermin and for direction and limitation of object (and their use must 
be cultivated), yet for accuracy, delicacy, and freedom from acoustic 
imperfection or injury from outside causes, nothing equals the tem- 
poral bone of the head, placed against the sonorous object, so that the 
sound vibrations may pass directly into it and to the organ of hearing. 
One may have occlusions of the Eustachian tube and the hearing will 
be impaired, or there may be injury of the drum and the person may 
be deaf, but if he is accustomed to receive sound impressions from 
vibrating bodies directly into the temporal bone, he will not lose his 
power of auscultation because he is deaf by injury of the drum. The 
whole side of the head is sensitive to direct vibrations delivered directly 
from a sonorous body. But the most sensitive part is in front and 14 
LEA MING, 
just above the external ear. Here, in this way, the nicest discrimina- 
tion of sound can be made, and, under the laws of acoustics, correct 
diagnosis. It is not affected by age, by the accumulation of dried wax 
in the ear, or inflamed throat closing the Eustachian tubes. It 
measures the time in the heart's cycle with unerring certainty and 
detects the slightest fault in rhythm, and, of course, detects the earliest 
evidence of pathological change in the respiratory murmurs-their 
analysis and cause, their locality and manner of conduction into the 
chest-wall-are all noted by this perfect acoustic instrument, a micro- 
phonometer. 
Sound is caused by vibrations which send off sound-waves into the 
air, the universal sound medium, spreading out in every direction 
until they finally die away from diminished force. Causes of primary 
vibrations are readily illustrated by air forced through a tube, by a 
tense cord over which a bow is drawn, by a bell, or a bar of steel 
fastened at one end, set in motion by a stroke of a hammer or other- 
wise. 
It is necessary, in order that the vibrations should produce sound- 
waves, that they should have definite force and frequency. The force 
of the primary vibrations must be sufficient to send off sound-waves 
into the air, and of frequency somewhere between thirty-two and forty 
thousand per second. Less than thirty-two per second produces a sensa- 
tion of distinct noises, and more than forty thousand ceases to give off 
sound-waves. The designations of high pitch and low pitch have refer- 
ence to the frequency of vibrations, and are of practical importance 
in determining the density of sonorous bodies under examination. 
High pitch denotes density, low pitch porosity. The pitch enables us 
to measure the number of vibrations in a second in any body under 
examination, determining the density; for, with an instrument called 
the siren, we can measure the number of vibrations in a second in any 
pitch, which brings acoustics under mathematical demonstration as an 
exact science, especially including auscultation of the human chest. 
There are other limitations of hearing than those of pitch and loud- 
ness, which are more readily understood by comparing them with 
color-blindness in sight, the persons with such deficiency in either case 
not being themselves aware of it. Engineers and flagmen on railroads 
are examined in regard to their perceptions of differences in color in 
the protection of the lives and bodily safety of the travelling public. 
Why should not also the medical student, before devoting himself to 
physical diagnosis, test himself, or have himself tested, in regard to 15 
ACOUSTICS OK THE HUMAN CHEST. 
clang-deafness1 before taking upon himself the responsibility of making 
delicate diagnoses where failure to appreciate the tone differences in 
the acoustic signs may lead to a plan of management fatal to the 
patient? 
These inquiries approach the domain of aesthetic taste at the same 
time that they have the solid foundation of practical truth. 
The entirely correct ear in auscultation gives its possessor pleasure 
in listening to natural sounds in the fields, in the forests, on the ex- 
tended plains, or on the mountain tops-all of which are but dreariness 
to one who has not that inner sense of the beautiful in nature depen- 
dent upon tone appreciation. 
In the wonderful music drama of " Siegfried " the natural sounds in 
the forest-the singing of birds, the drone of insects, the sighing of the 
wind among the leaves of the trees-are reproduced in music, the 
" Waldweben." The correct acoustic sense that fits the student for an 
auscultator will be delighted and appreciative; but the clang-deaf will 
not hear the melody. It must be noted that this higher quality of 
tone recognition is entirely different from memory of a tune, which is 
memory with a sense of time and rhythm only, and enables its pos- 
sessor to learn and sing " The Marseillaise" or " God Save the Queen " 
without any thrill of delight in their harmonious chords and spiritual 
suggestions. 
It is an interesting point to determine by trial whether the color- 
blind are also clang-deaf, which would show, if decided in the affirma- 
tive, that the deficiency is not owing to any mechanical fault in the 
structural formation of the organs of sight or hearing, but is essential 
in the organic or spiritual life of the body. One fact is demonstrable 
-that the senses of hearing and sight may be greatly extended in 
range and accuracy by cultivation. This is seen in experts in music 
and painting. Culture increases the power of discrimination and 
delight in color and in tone in the masses, while the exceptionally 
natural, sensitive sense of sight and hearing will be increased thereby 
to expert excellence. 
Primary vibrations may be conducted, reflected, or consonated. If 
there is in contact with the vibrating body another body or structure 
capable of being set into vibrations, the vibrations of both will be in 
unison; or, as in the case of the lung connected by adhesions to the 
chest-wall, or by intermediate structures, or by tense cord like adhesions 
1 Helmholtz uses this term to denote a tone with its accompanying overtones and 
partial tones. 16 
LEA MING, 
of any length, then the secondary body-as the chest-wall is when the 
lung is adherent-may give off sound-waves which will pass into the 
air the same as if coming from a primary source. The familiar 
example of direct conduction is the one given of scratching the end 
of a log with a pin by one person while another listens at the other 
end, fifty feet away, and hears by illusion the sound under the ear. 
In such a case there is no solution of continuity, nor is there in the 
consolidated lung, by which also there is direct conduction. Indirect 
conduction of sound takes place when there are adhesions of parts to 
parts adjacent, as of the pericardial sac to the lung, and the lung to 
the chest-walls, when the heart's sounds will be heard at the site of 
adhesion of the lung to the chest-wall, although the origin of the 
murmur may be in another direction and a long way off, and yet will 
seem to originate directly under the stethoscope, which fact may give 
rise to false diagnosis. For the natural intraventricular vibrations of 
a portion of the chordae are in sound-connection with the pericardial 
adhesion and are indirectly conducted into the chest-wall, are there 
heard as if originating under the ear, while there is no fault with the 
mechanism of the heart as a pump. This shows the fallibility of the 
stethoscope as an instrument of precision. The locality of the murmur 
in the chest-wall may be no guide as to the local mechanism or origin 
of the sound. 
Indirect conduction may be illustrated by the violin. The strings 
are caused to vibrate by the bow primarily, but these vibrations are 
conducted by the bridge into the front or belly, which is made of 
straight-grained pine cut so that each fibre may vibrate separately and 
in unison with the strings. The sound-post conducts these vibrations 
accumulatingly to and against the back of the violin, which is made of 
maple or sycamore wood of interlaced fibres which cannot vibrate in 
unison with the strings, but reflects the vibrations back into the air in 
the acoustic chamber. The sonorous material corroborates the vibra- 
tions at each passage from the strings to the bridge, from the bridge to 
the front, until they are reflected from the back into the body of pul- 
sating air within the violin, which finally passes them out of the sound- 
holes into the open air. 
Reflection of sound is the opposite of conduction, and in a sound- 
chamber prevents sound-leakage - in the violin through the back 
especially. In the human chest the pleural lining reflects equally 
from all directions. This acoustic fact becomes of diagnostic interest 
when adhesions connect the internal organs with the wall, or when 
they press against it, as when swollen, or are hypertrophied, etc. Then ACOUSTICS OF THE HUMAN CHEST. 
17 
sound-leakage takes place. Echoes are reflected sound-waves, either 
parallel or converging. Reflected sound pertains altogether to sound- 
waves-not to primary or conducted vibrations. 
Consonation also has to do with sound-waves alone. It has nothing 
to do with primary or conducted vibrations. Let one sing before a 
sensitive violin, and each string will be made to give sound vibrations 
whenever its fundamental note is sounded. Consonation is one of the 
most frequent phenomena of the human chest, and is constantly made 
use of by auscultators practically in searching for consolidation of the 
lungs or interplural adhesions or cavities, by sounding the voice in 
phonation, or whispering, or by the cough. Dr. Holden, of Newark, 
N. J., introduced a little instrument to the profession a few years ago 
which illustrated consonation practically. It was an India-rubber 
tube an inch in diameter, about fourteen inches long, with a metal 
mouth-piece at either end. The patient would breathe through the 
tube forcibly so as to create air friction, while the auscultator would 
listen to his chest. If there were adhesions or any condensation of 
lung-tissue, it would be made evident at once by consonation and by 
the conducted sounds heard through the chest-wall; also, if there 
were cavities at the same time, it would diagnosticate them from 
tumors or consolidations, which otherwise may not so easily be done. 
When these principles of acoustics are applied-consonation, re- 
flection, and conduction of sound-an interior view of the chest is 
opened to us as through a window. Much more is this evident in dis- 
ease when we have previously applied these principles to the conditions 
of health. 
The lungs fill the sound-chamber and envelop the heart, with the 
exception of the apex-beat area. They are non-sound-conducting ex- 
cept in one direction-in that of the columns of air in the convective 
or air-conducting tubes. 
The little group of air-sacs, six to thirteen in number, developed 
at the terminal ends of the air-tubes of the true respiratory system, 
forming a lobulette, do the principal work of aeration of the blood 
the alveoli of the distensible tubes being but supplementary to those 
of the air-sacs. The delicate muscular fibres over each alveolus and 
each air-sac contract upon the contained air, which is constantly ex- 
panding under the influence of heat; and sound vibrations are thus 
caused during inspiration, and especially at its full; individually 
small, but collectively forming a body of sound of low note. This 
murmur is significant of the healthful action of the vital process of 18 
BEAMING, 
respiration. If its process is interfered with by paresis of the envelop- 
ing muscular fibres, which always takes place in emphysema or in 
tuberculosis, the muscular susurrus, the true respiratory murmur, will 
not be heard. But when the disability is but temporary it is interest- 
ing to watch the gradual return of the murmur under successful treat- 
ment. 
In centric pneumonia there is no other physical sign than the true 
respiratory murmur, except slightly raised pitch under percussion. 
This acoustic condition may remain scarcely changed for three or four 
days, but as soon as the pneumonic process has reached the pleural 
surface, immediately the physical signs show the fact. At once are 
heard interpleural rales and bronchial breathing, which denote con- 
solidation of the lung and increased conduction of sound from air- 
friction in the tidal air-tract. The pneumonic condition existed just 
the same while there was yet no adhesion, but instantly became evi- 
dent when sound-connection was established. 
The early recognition of centric pneumonia gives time to prevent 
the pleural complications; a very important matter as regards patho- 
logical results. The greatly diminished true respiratory murmur over 
a definite area, corroborated by the slightly raised pitch, fixes the 
locality, completes the diagnosis. 
To those who do not recognize the true respiratory murmur from 
want of attention or from imperfect sense of hearing, these cases are 
puzzling, for the rational signs indicate in a doubtful way the pneu- 
monic state, pulse, temperature, and respiration slightly increased, with 
bloody or rusty sputa. 
The recognition of the absence of true respiratory murmur in the 
centre of the lung will enable the auscultator to make a correct diag- 
nosis and to predict a sudden augmentation of all these signs and 
symptoms, physical and rational, in a given time-i. e., just as soon as 
the pleura becomes involved, and the gluey exudation forms sound- 
connection between its surfaces. 
In the normal chest the freedom of movement of the pleural sur- 
faces gives evidence of health. For, as the lungs fill with air and 
the chest-wall expands, each little lobulette travels a little distance in 
inspiration and back again in expiration. If the ear or stethoscope is 
placed against the chest-wall, a multitude of these little resonating 
air-sacs, each attached to a terminal bronchus-a minute speaking-tube 
-will pass under review and give sound vibrations: first, of themselves 
in the true respiratory system; second, of the air-friction in the tidal 
air-tract-which extends from the entrance into the mouth and nostrils, ACOUSTICS OF THE HUMAN CHEST. 
19 
into the respiratory passages, down as far as to the fourth division of the 
bronchi-in which the air moves in a body; and, third, outside noises. 
Respiratory murmurs are composed of these three elements, which 
are all intensified by passing rapidly in review in a lively movement 
of the lungs under the ear in auscultation. Interpleural adhesions 
fixing the lung in one place are denoted in this way, by the feeble 
respiratory murmurs, even when the air-sacs are free to contract and 
dilate as usual. 
Every elastic air-sac dilated with compressed air is a resonator, the 
sounds consonated in which are, first, sounds outside of the body. 
Auscultators for this reason choose a quiet room in which to make 
their examinations, and sometimes, too, make the mistake of attempt- 
ing to exclude outside noises by closing the opposite ear with the 
finger, which adds unnecessary confusion and shuts off nothing but 
their fixed attention. Second, the air-friction sounds formed in the 
tidal air-tract, which are conducted to and consonated in the air-sacs, 
such as sounds of dryness or of roughness, of mucous rales, and of 
foreign bodies. 
In the first stage of acute bronchitis the mucous membrane is dry 
and rough and the air-friction gives sounds accordingly, which are 
conducted to the air-sacs by the bronchial tubes, in which they are 
consonated with increased intensity. Mucus formed within the 
bronchia moves forward and backward in inspiration and expiration, 
causing mucous rales, which also are conducted to and consonated in 
the air-sacs, especially when adhesions increase the conduction into 
definite localities. Many times the mucus and the rales are both im- 
mediately removed by coughing and expectoration. The mucus is a 
foreign body, and, like all foreign bodies, should be removed. 
The following cases are briefly referred to as evidence of the value 
of acoustic signs in diagnosticating the presence and locality of foreign 
bodies in the air-passages : 
Case I. A Spanish silver shilling diagnosticated to be in the third 
division of the right bronchus.-A man, hurrying to catch a ferry-boat, 
put the coin in his mputh for convenience, and during a forcible in- 
spiration it passed through the larynx. He came to me in the after- 
noon of the same day and told me that he had " swallowed " a shil- 
ling, and that he thought it was in the lungs. I then believed that it 
was impossible that a foreign body could pass the epiglottis. Dr. 
Horace Green had then but lately announced his ability to pass a 
catheter through the larynx. A committee appointed by the Academy 
of Medicine, after experiment and inquiry, had reported its impassa- 20 
BEAMING, 
bility. I told the patient so, " but," said he, " I think I can feel and 
hear it here," placing his hand upon his chest. I listened and heard 
a " flap " in just about the fifth interspace in the right side. Keeping 
my ear to the chest, in a few moments there was another " flap," send- 
ing the sound in another direction. I soon discovered that after each 
" flap " a certain area of the chest-wall ceased to transmit respiratory 
sounds, which only lasted until the next " flap," when another area of 
the chest-wall became quiet. I was convinced that the coin rested its 
edge upon the septum of the third division, and, valve-like, turned 
back and forth as the newly inspired air underneath became rarefied 
by heat. I directed him to get on his bed and place a cushion on the 
floor near the bed, and then suddenly to turn down and bump his 
head upon the cushion, which he did, and the coin was expelled with 
an explosive cough. 
Case II. Through the kindness of Dr. W. W. Jones I saw a man 
who, three days before, had passed a head of timothy through his 
larynx. He had placed the stalk between his teeth and was chewing 
it while giving directions in his stable, and, suddenly attempting to 
call to some one at a distance, he drew in his breath, and with it the 
dry head of timothy. One can hardly imagine a more frightful 
calamity. He coughed some, but did not think it necessary to send 
for Dr. Jones until the next morning, and even then he did not believe 
the timothy had passed the larynx, the symptoms were so much less 
than might have been expected. But they gradually became serious, 
and on the third day I was called in to auscultate him. There was 
then no true respiratory murmur and there were interpleural rales 
over both lungs, but on the right side there was conducted bronchial 
breathing down so low that I thought it involved the liver. The next 
day he coughed and vomited up a large amount of muco-pus, and in 
it was the denuded stalk of the timothy-head, after which there was a 
cavernous respiration. The autopsy showed abscesses in both lungs 
and extensive interpleural adhesions. 
Case HI. Blood in the right bronchus and lung.-This occurred in 
a surgical case in St. Luke's Hospital, New York. A man was 
operated upon, while under the influence of ether, for the removal of 
dead bone in the jaw caused by phosphorous poisoning. While un- 
conscious the blood trickled through the larynx and bronchia into the 
true respiratory system beyond the tidal air-movement, where it 
speedily putrefied and formed abscesses which caused the patient's 
death. I saw the patient each day and was able to note the physical 
signs. The first day there were conductions of bronchial rales, caused ACOUSTICS OF THE HUMAN CHEST. 
21 
by the moving blood within the tidal air-space, and obstruction of the 
true respiratory murmur. The next day there were interpleural rales 
over both lungs, although the blood had passed mostly into and 
through the right bronchus. On the third day there was local peri- 
bronchitis with consolidation of the surrounding lung. On the fourth 
day there were moist rales in and around the consolidations. On the 
fifth there were cavities. On the sixth day there was general acute 
plastic exudation over both lungs. He died on the seventh day. The 
post-mortem showed that the pathological processes had been accom- 
panied by the acoustic signs in each particular. The case was an 
" object lesson " of value to me-full of instruction in regard to the 
treatment of bronchorrhagic hsemoptysis, and makes plain the danger 
of attempting to arrest bronchial hemorrhage for fear of getting a 
clot below the tidal air-tract, where it rapidly causes destructive in- 
flammation and cavities, and the patient dies, as is said, but which is 
a mistake, of " acute phthisis." 
Case IV.-The next case in time was Dr. Gurdon Buck's-a trache- 
otomy-tube in the right bronchus of a patient at St. Luke's Hospital- 
an account of which he published. 
A man came into the hospital with gummy tumor occluding the 
larynx, and immediate tracheotomy was necessary. The next day the 
opening was enlarged and the tumor removed, and a tracheotomy-tube 
of hard rubber was introduced, corked, and tied with a tape at the 
back of his neck. This was for safety in case any sudden swelling 
should obstruct the larynx, and he was allowed to walk about the 
grounds and corridors. After three or four days, on awakening early 
in the morning, he discovered that the tube was gone. " The House," 
Dr. Riggs, and " the Junior," Dr. Lefferts, were at once called, but 
the tube could not be found. At Dr. Buck's request I auscultated the 
patient and found acoustic evidence of the tube in the right bronchus. 
It had dropped down and the lower end was engaged in the very 
short first division, which is subdivided into two or three bronchia 
distributed to the apex of the lung. Over this region alone the air 
friction in the tube could be easily heard. A consultation of all the 
surgeons and physicians of the hospital was called for the next day, 
and the tube was removed with a curved forceps. 
Case V. A molar tooth " swallowed " by a man while etherized at St. 
Luke's Hospital.-The House Physician, Dr. Lefferts, diagnosticated 
its presence in the left bronchus, but the patient utterly refused an 
operation until destructive inflammation had done its work. Dr. Lef- 
ferts requested me to auscultate the patient, and I confirmed his 22 
LEAMING, 
diagnosis. The tooth was impacted just above the third division of 
the left bronchus, and two abscesses in the lung below had resulted. I 
have a photograph of the tooth in the bronchus, kindly given me by 
Dr. Lefferts. 
Case VI. A collar-stud in the right bronchus, occurring in the prac- 
tice of Dr. J. T. Kennedy.-A boy playing ball, becoming very warm, 
took off his collar, and put the bone stud between his teeth, but, 
attempting to shout to another boy at a distance, the stud was carried 
through the larynx by inhalation into the right bronchus. It caused 
some irritation and cough, but his discomfort was not great. After 
some days, perhaps weeks, Dr. Kennedy brought the boy to my office 
for auscultation. There was acoustic evidence of a foreign body in 
the right bronchus, just above the third division, the broad button 
side of the stud being pressed against one side of the bronchus and the 
cone end against the other side, and the shank extended between. 
After a time plastic exudation took place in the pleural cavity and in 
the lung, and the father, who had before refused, consented to an 
operation, which was tracheotomy, and was performed by Dr. Markoe, 
who removed the stud with a curved forceps. 
Case VII. Dr. Lefferts's removal of a brass ring from a boy's larynx 
by operation.-A brass wire, bent so as to make a nearly closed ring, 
was in a child's mouth, and a woman, endeavoring to get it out with 
her fingers, pushed it below the epiglotis. It remained there about two 
years, although the child had been taken to clinics and to different 
doctors without relief. By the kindness of Dr. J. L. Smith, the boy 
was sent to my office, and the ring was traced acoustically to the 
upper part of the larynx. I sent this patient to Dr. Lefferts for 
laryngoscopic examination, who confirmed the acoustic diagnosis, and 
removed the ring by an operation. The case was published by Dr. 
Lefferts. 
Case VIII. A man with part of a peach-pit in the right lung.-After 
several months it was coughed up, but not until it had caused perma- 
nent injury to the lung. In the meantime he was frequently exam- 
ined at my office, the acoustic evidence showing that it had passed 
beyond the tidal air-tract. 
Case IX.-A child, about two years old, "swallowed" a plum-pit, 
and it passed through the larynx and into the right bronchus, but its 
exact location was difficult to make out, because the child could not 
be kept still enough for a careful examination, and also because the 
true respiratory murmur is not fully developed until after twelve 
years of age, but it was presumably in the tidal air-tract. It was ACOUSTICS OF THE HUMAN CHEST. 
23 
finally coughed up, being assisted by a blow upon the child's back by 
its mother. 
Case X. Dr. J. A. Wyeth, at Mount Sinai Hospital. A little dart, 
made of a pin and yarn, used by children to blow through a tin tube at 
a target, in the right bronchus.-The boy inhaled, and the dart passed 
through the larynx and into the right bronchus. By the kindness of 
Dr. Wyeth, the late Dr. Elsberg and I were requested to examine the 
boy. Dr. Elsberg could see its shadow with the laryngoscope, and I 
had acoustic evidence of its presence just above the third division of 
the right bronchus, and that it moved up and down in respiration as 
thickened mucus frequently does. Dr. Wyeth performed tracheotomy, 
and the dart was removed. 
These interesting cases of foreign bodies in the air-passages are sum- 
marily alluded to for one purpose only-to show with what certainty 
their presence can be ascertained by applying the laws of sound in 
auscultation. 
I have already given an explanation of the mechanism of the heart's 
sounds as agreeing with acoustic law. In studying the philosophy 
of murmurs we must remember that the heart is inclosed in a sound- 
chamber, enveloped in a non-sound-conducting medium-the lungs 
-with the exception of the apex-beat area, in which the heart has 
sound-conduction into the chest-wall in perfection only while the 
heart is in contact with it. There is at all times more or less con- 
duction of sound, because of the immediate connection of the peri- 
cardium with the heart while in sound-connection with the chest-wall. 
So that the first sound (and the murmurs connected with it are the 
only ones formed within the heart) is heard in its entirety from its 
commencement until it is ended with, and emphasized by, the apex- 
beat. The second sound is formed by the forcible closure of the semi- 
lunar valves by the return blood in the aorta and pulmonary arteries. 
It is a door forcibly closed, and the sound is conveyed through the car- 
diac wall to the apex-beat area by conduction. It is also conveyed 
through the mediastinum into the sternum and adjacent chest-wall of 
the left side. The closing of the semilunar valves of both the pul- 
monary artery and of the aorta have the same source of conduction, 
the mediastinum, and into the same area. The different areas marked 
out by teachers and writers as the separate localities of these murmurs 
have existence only in their imagination. Because there are two sets 
of valves, a very short distance apart, it was imagined that there must 
be two areas, and so they were marked out. 
Both hearts contract in absolute unison, the valves close in the same 24 
LEANING, 
moment of time, and there is perfect synchronism of the two heart's 
sounds-the first and the second. And the intervals of silence must 
remain in exact synchronic proportion so long as the heart remains in 
perfect mechanism as a pump. The perfect rhythm of the heart's 
sounds and intervals of silence in the cardial cycle becomes absolute 
proof of its perfection as a pump. The heart may be weak, irritable, 
and irregular in its action, but if the rhythm of the sounds and inter- 
vals of silence in the cycle is correct, there is no valvular incapacity, no 
matter what may be the disturbed action of the heart or the number 
and location of its murmurs. But as soon as the rhythm is altered, its 
extent ■will measure the amount of injury the heart has received, and 
then the murmurs of obstruction and regurgitation will point to the 
locality and nature of the disease. 
Obstruction of the aortic orifice will cause a murmur which, by con- 
duction of the mediastinum, will be heard at its point of attachment in 
the sternum and to a short distance into the chest-wall of the left side. 
It will also be heard in the course of the aorta, and especially in the 
right border of the sternum, through the attachment of the aorta to 
the chest-wall, for at these points there is indirect conduction of vibra- 
tions through the stream of blood into the chest-wall. The aortic and 
pulmonary signs part company at the first point in sound-convection 
through the mediastinum into the sternum which they have in common 
over the aortic valves. 
The murmur vibrations at the right border of the sternum come 
through attachments to the aorta alone, and are conveyed in the stream 
of blood from their origin at the aortic orifice. 
The regurgitant murmur at the aortic orifice will be heard in the 
sternum through the mediastinum, sometimes extending to the xiphoid 
cartilage, or in the stream of regurgitated blood against the heart's 
wall and into the chest-wall about half an inch from the valve, but oc- 
casionally to the apex-beat, this depending upon the force of the vibra- 
tions. So that the diagnoses of lesions of the aortic orifice and valves 
are generally easily made out, but the feebleness of the regurgitant 
murmur at times renders its recognition of difficult appreciation to 
those who have a limited sense of hearing, or where the acoustic con- 
ditions of the chest have been altered by inflammation of the lungs, 
or by effusion into the pleural cavities, or by hypertrophy of the heart, 
or contraction of the chest-wall bringing it over a large space into 
sound-contact with the heart. 
Lesions of the mitral valve cause murmurs. The obstructive will be ACOUSTICS OF THE HUMAN CHEST. 
25 
heard at the apex-beat area alone, but the regurgitant almost exclu- 
sively over an area at the back near the spine, between the seventh 
and eighth vertebrae of the left side. The stream of regurgitant blood 
strikes upon the wall of the left auricle, which lies in sound-contact 
with the cesophagus, the aorta, and the intervertebral cartilage. When- 
ever the murmur, the acoustic sign, is absent from this area, it may be 
safely asserted that there is no regurgitation. If there are no condi- 
tions causing intraventricular murmurs-that is, unusual vibrations of 
the chordae tendineae-the true regurgitant murmur may be conducted 
through the cardiac walls backward to the apex-beat area. But this 
is of rare occurrence, and can only be the case when plastic exudations 
upon the chordae prevent their sound vibrations, or where the imper- 
fection of the mitral valve is congenital and does not affect the normal 
vibrating conditions of the chordae. Otherwise their excessive sound- 
vibrations drown those of the mitral lesions. These unnatural vibra- 
tions of the chordae, representing so-called mitral obstructive murmurs, 
demand special attention, as their frequent misapprehension is the cause 
of disastrous false prognostications. 
We have endeavored, heretofore, to show that the joint sound-vibra- 
tions of the chordae and the mitral valve in health give us the perfect 
first sound. Any cause, within the heart or without, affecting the 
natural vibrations of the valve and chordae, will alter the joint sound 
and cause an interventricular murmur, so sensitive are they to acoustic 
law. 
If obstruction at the aortic orifice occurs, requiring greater muscular 
contraction of the ventricular wall, the cardiac muscle, following the 
universal law, hypertrophies under the increased exertion. Hyper- 
trophied cardiac walls with greater power of contraction increase the 
tension of the chordae, multiplying the vibrations, and the raised pitch 
causes discord in the first sound, and becomes a multiform apex-beat 
murmur. Plastic deposit on the valves or upon the chordae, lessening 
their vibrations, will also cause a murmur. Whenever a murmur is the 
result of physical change it is properly an organic murmur, even when 
it may be removed by treatment. 
There are other forms of interventricular murmurs: those owing to 
neurotic conditions outside of the heart, as from chorea, from exhaust- 
ing hemorrhage, or from nervous excitation of any kind. Another fre- 
quent cause is adhesions of the pericardial sac to the lung, and of the 
lung to the chest-wall, producing an interventricular murmur conducted 
into the sound area of the adhesions, even when there is no lesion in 
the heart, which might deceive the very elect were it not for the con- 26 
ACOUSTICS OF THE HUMAN CHEST. 
tinuance of perfect rhythm of the heart's cycle. These murmurs are 
conducted often through a portion of condensed lung, which fact being 
made out is confirmatory evidence of the general innocuousness of these 
murmurs-such as are frequently heard in the space around the apex- 
beat area, where the heart is covered by a thin portion of the lung, and 
for the same reason over the region of the pulmonary artery. Many 
times they are merely conducted sound-vibrations of the chordae, and 
do not at any time necessarily denote organic disease of the heart. 
If the heart wTere removed from its case and envelopment of lung, 
still performing its functions, we might hope to arrive with greater 
certainty at the knowledge of the exact local action of valvular mur- 
murs. We could then place the ear or the stethoscope against the 
heart itself in search of the evidence of organic change. We could 
at least eliminate the outside causes of false murmurs by conduction. 
But the source of vibrations from valvular diseases or relative change 
in the capacity of the different chambers would still be within the mus- 
cular walls of a closed chamber, and absolute certainty could not be 
arrived at in that way. Is it, then, a wonder that we fail sometimes to 
make correct diagnoses by the ordinary methods in which we have been 
taught? But the application of the laws of acoustics is like intro- 
ducing an electric light into the chambers of the heart and reading 
their secrets as by the light of day. 
I have endeavored for many years past to make auscultation of the 
human chest scientific and more certain by the application of acoustic 
law. If I have in any degree succeeded in directing the attention of 
the profession to the practical application of the laws of sound in diag- 
nosis of the chest, I shall be well satisfied. INTERPLEURAL PATHOLOGICAL PRODUCTS: THEIR 
CAUSE, SIGNIFICANCE, AND SPECIFIC RELATION- 
SHIP TO PULMONARY PHTHISIS. 
By J. R. LEAMING, M.D., 
NEW YORK. 
Eeprinted from the Transactions of the American Climatological Association, 
September, 1888. INTERPLEURAL PATHOLOGICAL PRODUCTS: THEIR 
CAUSE, SIGNIFICANCE, AND SPECIFIC RELATION- 
SHIP TO PULMONARY PHTHISIS. 
By J. R. LEAMING, M.D., 
NEW YORK. 
The normal healthful pleurae are free in movement. Their surfaces 
glide over each other in respiration without sound-producing friction. 
They cover the lungs and their lobes, the inner costal walls of the 
chest, the outer surface of the pericardial sac, and the mediastinum. 
Thep are not only smooth of themselves, but they are lubricated by a 
natural secretion never in excess and never absent. 
Unfortunately, the normal healthful condition of the pleurae is 
not what is most frequently found in post-mortem examinations, 
for seldom are they entirely free from pathological results. The 
early pathologists, finding these conditions of such frequency and 
without history of illness as cause, looked upon them as normal. It 
is not yet twenty years since Dr. Flint, standing in the very front of 
medical renown, whose memory we revere and of whose fame we are 
proud, in leading the discussion of a paper on pleuritis which I had 
the honor of reading before the New York Academy of Medicine, 
said, in effect, and not unkindly, that the profession would not agree 
with me in my estimation of the causes, pathology, physical signs, or 
treatment of interpleural adhesions; that they were not discoverable 
by auscultation, had no effect upon the health of the individual, and 
could not be reached by medication. There is no doubt that Professor 
Flint truthfully represented the verdict that would have been given 
by the profession throughout the world, could it have been taken, at 
that time. But since then, many advanced pathologists have adopted 
other views. Sir Andrew Clark, especially in his Lumleian lectures of 
three years ago last spring, gave a very thorough and clear account of 
interpleural pathological products, without acknowledgment of any 
American assistance. My early connection with this subject, if I am 30 
BEAMING, 
not, indeed, the earliest one to draw attention to it, is, I suppose, the 
reason that I have been invited to bring it before you at this time. 
Laennec and Louis refer to saddle-leather creaking sounds as being 
due to old cartilaginous adhesions within the pleurse. But all other 
rales and rhonchi were believed to be interpulmonary or interbronchial. 
But the application of the laws of sound points out unerringly their 
location and mechanism, and furnishes the elements of a correct diag- 
nosis. 
Pathological products within the pleurae are foreign elements, 
whether they are growths, like cancer, or benign tumors, tubercle, or 
other neoplasms; or whether they are exudates, the result of inflam- 
mation, or of depressed vitality-of which I shall have much to say 
in this article. 
Of tumors or neoplasms, benign or malignant, I shall not discourse, 
not intending to be exhaustive of the subject of intrapleural pathology, 
but shall confine myself to the two forms of exudates-sthenic and 
asthenic, which may influence or cause phthisis pulmonalis. 
The interpleural exudates which interest us in this discussion are of 
two kinds: First, those which are the result of active inflammation, 
such as pleuritis or pleuro-pneumonia; second, those which result from 
depressed organic life. The first is the one generally had reference to 
when the subject is under consideration. 
At the discussion which followed the very able papers before the 
New York Academy of Medicine, led by Dr. Westbrook, on the sub- 
ject of interpleural exudations as causes of consumption, the sthenic 
was the only form considered. That lowers the organic life by its 
mechanical pressure upon the organs, shutting off the circulation by 
closing the capillaries for nutrition and for aeration of the blood in the 
lungs. There is more or less natural tendency to remove this foreign 
factor by the absorbents, and the effort is successful or not according 
to the degree of vigor of the organic life in the body. 
There is no question that they depress the vital force mechanically; 
but they have no other phthisical tendency. Such seemed to be the 
apprehension of this subject by the New York Academy of Medicine. 
But there is another cause producing exudation within the pleurae 
which is not preceded by inflammation or rise of temperature. In- 
deed, many times the temperature is subnormal before and at the 
time of its exudation, which soon commences to contract, and the tem- 
perature to rise, or to vacillate from below to above the normal. This 
cause is within the life of the individual, is a part of it, and is imma- 
terial ; while the first causes are exterior to the life and are material. INTERPLEURAL PATHOLOGICAL PRODUCTS. 
31 
There is a trinity of life in man: The organic; the intellectual; the 
moral or responsible. 
Life, like heat and electricity, is known only by its manifestations. 
Let us study the beginning of these manifestations of organic life, as 
Harvey did with the eggs of the hen during incubation. After the 
first day, upon opening the shell, it was found that the relative 
positions of the yolk, the white, and the germinal spot or eye were 
changed, and that the white began to be a little turbid. This was the 
first manifestation, and proved that the hen had been with the cock, 
for the eggs of the hen which had not been with the cock did not show 
these changes. In them were no manifestations of life, and there was 
no life, for an unfertilized egg is dead. In the fertilized egg before 
incubation the life is inchoate, and by incubation it is warmed into 
manifestations. At the end of the second day the changes are still 
more marked, and at about the beginning of the third day a little 
point of red appears in the germinal spot, pulsating. This is the 
beginning of the circulation of the blood before there is a heart, 
proving that the rhythm and pulsations are primal manifestations of 
organic life, which then commences to build-first the right auricle 
and ventricle, and afterward the left heart. Finally, the arteries still 
shooting out, the whole body is formed in completeness. This organic 
life-the builder, is immaterial. It uses the prepared organism of the 
egg as the mason does the brick and mortar, the stones and cement 
provided for him. It shapes the building in form and for use. 
The immaterial essence which results from sexual congress, and 
which builds the material body, preserves its identity as an individual 
from the moment of conception until its final death, or until its mani- 
festations cease in the material world. But as organic life always 
manifests itself in form as well as in motion, we see the spermatozoa of 
the male with its distinctive form and locomotion by which it reaches 
the ovum of the female and is destroyed and a new creature begun. 
In the fable of Dionysius or creation, representing in Greek myth- 
ology desire or love-"Semele, Jupiter's paramour, made him take an 
inviolable oath to grant her one wish, whatever it might be, and then 
prayed that he would come to her in the same shape in which he was 
used to come to Juno. The consequence was that she was scorched to 
death in his embrace." 
The form of the individual continues during life, modified by age, 
accident, or disease-also the form of the organs, the members, and 
the constituent parts, the blood-disks, the cells of all the tissues, and 
the secretions. Everything that has life has inherited its form, its 32 
LE AM ING, 
limit of age, and transmits the same to its children-not only the 
essential inherent qualities of the individual but, many times, acquired 
peculiarities. So that disease forms and tendencies may also be in- 
herited-not the material, but the immaterial. 
The building material in each individual is introduced into the 
blood from the digestive organs, and is vivified and used to build or 
repair the form, which, as it grows old and dies, is thrown out of the 
system, and fresh, new material takes its place. The life and form 
continue, and are continually modified by time until the limit of the 
age of the individual is reached, when formation ceases and form 
decays. The most absolute proof of the immateriality of life is its 
death; because the dead body is proof of its former life. The excel- 
lence of Lord Byron's beautiful simile in " The Giaour," in the de- 
scription of " Greece, but living Greece no more," depends upon the 
appearance of form simulating life : 
Before decay's effacing fingers 
Have swept the lines where beauty lingers. 
Bone is the evidence of the once living animal. Hamlet, with 
Yorick's skull in his hand, reasons upon the former life of its occupant 
until his " gorge rises," and he puts it down in disgust, but goes on in 
his illustration by citing the dust of Alexander and that of Csesar in 
decay, and suggests the vile uses to which they might come. Wood is 
the evidence of the life of the tree, and of its growth from the seed; 
the identity of the life remaining ever, for the wood was always cedar, 
mahogany, or oak, as was the seed from which it sprang. The life 
remained, although it often changed particles-the particles which it 
took up from the ground and assimilated always making cedar, 
mahogany, or oak, never losing identity, for a thousand years or 
more, a continual evidence of the immateriality of life in the tree as 
in the animal. And the wood remains the death-evidence of the life 
of the tree for thousands of years afterward. 
The diamond, the ruby, or the sapphire are evidence of the imma- 
terial Creator. "The earth was without form and void." Divine 
creative energy flashed through these elements and crystallized them 
into gems of particular form, brilliancy, and hardness, or of rocks 
enduring, or of ores of precious metals, where they ever remain 
evidence of the eternal immaterial existence of the Creator. The 
crystal, the tree, the animal, represent the primal creation. 
Man is mortal-the race immortal. There is an endless succession 
of individuals, each filling his allotted time and then giving way for INTERPLEURAL PATHOLOGICAL PRODUCTS. 
33 
his successor. Each constituent molecule is mortal, like the individual 
man. It has its limited time of existence, and then passes away and 
gives place to a new one-and the succession goes on during the exist- 
ence of the individual. It has its predecessor and successor, and with 
them its acquired tendencies to disease. These are laws impressed 
upon all organic life-heredity and endless succession. The organic 
life, besides pervading every constituent part of the body, has its par- 
ticular home in the great sympathetic nerve. A connected series of 
ganglia near vital regions massed together in plexuses are reservoirs; 
each ganglia, however, is in a measure, independent, yet all are joined 
in sympathy with each other and with the unity of the individual. 
Filaments accompany each artery, vein, and capillary. The organs 
of special sense, the heart, lungs, kidneys, liver, stomach ; of digestion, 
of secretion, of generation; even the brain, which itself was created 
for the home of the intellectual life, is in every part of it supplied with 
organic life. The brain could not emit a single thought or emotion with- 
out the active assistance of organic life. We learn of the intellectual 
life through its manifestations. The feeblest brain-effort of the newt to 
its highest development in man is recognized only by its manifestations. 
Both the newt and the man seek their food, defend themselves from 
danger and attack, and propagate their kind. Their intelligence differs 
with corresponding differences of brain-development. The chief mani- 
festations of the lower animals are locomotion with definite purpose. In 
man the manifestations are of greater extent and greater power, with 
the capacity for improvement by education. But what distinguishes 
man from all other animals is a manifestation of another kind of life 
-a moral life, or conscience. The manifestations of this new life may 
be very feeble, but they are distinct, and the power admits of educa- 
tion, like that of the intelligence. It is quite certain that each may 
be educated separately or in unison ; but, if separately, resulting in a 
moral monstrosity. The trinity of life in man may be thus stated : 
First, the organic (the builder)-the life of the body; second, the in- 
telligence-the life of the soul; third, the conscience-the life of the 
spirit; body, soul, and spirit all immaterial-each known by its mani- 
festations only. The evidence of the immateriality of the life of the 
body is in its manifestations as builder. We could know nothing of 
them but by building the form of the material body in all its parts, and 
as a whole; its mysterious conception-intra-uterine existence and 
birth, and independent life through the periods of infancy, childhood, 
youth, manhood, old age, and natural death. Intellectual life com- 
mences after birth, noticing outside objects, learning its relationship 34 
BEAMING, 
to the outside world, feeling pain, showing pleasure, fear, or joy. The 
manifestations increase with the growth of the body and the successive 
stages of periods of age, until decline and death. The soul, too, grows 
old. Its habitation, the brain, is part of the body; and as the body 
grows feeble by age, the intellect must give feebler manifestations, ac- 
cording to the waning power of the body, and the brain, its instrument. 
The manifestations of the spirit commence only when the soul upon 
which it depends has arrived at some degree of capacity for intelli- 
gence. All human laws recognize this fundamental truth, for the 
child is not held responsible for its acts until it has arrived at the age 
of discretion. Responsibility is measured by intelligence. Intelligence 
is limited by the development of the body. This delicate interdepend- 
ence may become deranged at any time during the life of the indi- 
vidual. It is frequently temporary, as in fevers, or in intoxication 
from medical agents, or commonly by alcohol; or may be more or less 
permanent, as in pathological conditions of the brain, or reflex, in 
sympathy with organic disease in some other part of the system of 
organic life. This higher development of the animal in body and 
soul, with the added form of spirit or moral life, belongs alone to man. 
" Conscience makes cowards of us all," is an appreciation by the poet 
of the spirit's power, for good or evil, over the physical organism. It 
dominates with controlling force in nutrition, in pathological condi- 
tions of atoms as observed in the intimate structure and in the blood. 
This power is in contradistinction with the outside agents which affect 
the life of the body-such as poison of different varieties brought in 
contact with the organic life, externally or within; or miasma, which 
is simply another form of poison; or microbe, especially the bacillus 
tuberculosis. The modus operands of these agents is difficult of ex- 
planation, but the practical fact remains that tartarized antimony will 
cause emesis, or that croton oil will produce catharsis, and that other 
agents the same or similar effects or different ones, and that we make 
use of our experimental knowledge of them in the treatment of dis- 
eases. Again, it is just as difficult to explain how the materies morbi 
which may come to us in the air which we breathe or in the food we 
eat-miasmatic or microbic-should always produce in the organism 
the same diseases. There is nothing a priori in the constitution of the 
materies medicatrix or of the materies morbi which will explain their 
peculiar and characteristic effects upon the living organism. We are 
forced to the conclusion that the peculiarity of the invariable effects of 
these exterior agents is not in the agents themselves, but in the organic 
life-for if the life has gone out of the body, these agents have no INTERPLEURAL PATHOLOGICAL PRODUCTS. 
35 
similar effect. Calomel or other preparations of mercury applied to 
the dead body produce no characteristic effects, as they invariably do 
when applied to the living organism. And so with all other medical 
agents or poisons, or disease-germs. They are exterior causes which 
have power to influence the interior life of the body for health or for 
disease. But the spirit is a potent factor in preserving health or in 
causing disease, and its action is not less mysterious upon the organic 
life than is that of the materies morbi or the materies medicatrix. 
This interior cause which dominates the life of the body through the 
life of the soul, although depending upon them for its life, controls 
their healthful manifestations when benign, or of disease and death 
when malign. It may cause death of the body by first causing death 
of the atoms, instantly or successively. When malignly influencing 
the atoms, causing their immediate or successive death, it gives rise to 
diseases of the body similar to those produced by the materies medica- 
trix or materies morbi. With the tissues and circulation filled with 
these dead and diseased atoms, the organic life attempts their expul- 
sion by crowding them through the walls of capillaries into the natural 
cavities of the body, notably the pleurae and the cellular tissues. They 
are not all dead atoms, but diseased, and when thrown out of the 
systemic circulation they still have enough vitality left for organiza- 
tion, imperfect though it be. The immediate action of this pseudo and 
imperfect organization is to contract, and in this manner to cripple the 
functions and manifestations of the organic life in local areas of the 
physical body. The pleural cavities are the great dumping-ground of 
the organic life. Here pathological products are more frequently 
found, and when of much extent their contraction mechanically closes 
the capillaries of the lungs upon their surfaces, preventing largely 
the aeration of the blood, and, all of the malign causes continuing to 
operate, the disease becomes progressive fibroid phthisis. The tempe- 
rature, perhaps, always is subnormal in the earliest stages of exudation. 
But when contraction commences after adhesions, the local irritation 
causes the temperature to rise at irregular times, and vacillates from 
below to above normal. It is frequently a sign of organic feebleness 
and a losing struggle in the battle of life. 
Physical and pathological conditions similar to these followed the 
severe storm of last March in New England and New York, known as 
the blizzard. It will be remembered that the temperature was low- 
about zero-and that the winds were very high and the atmosphere 
loaded with fine particles of ice. The result was, many times, dis- 
astrous to those obliged to travel on foot for any length of distance. 36 
BEAMING, 
The exertion was constant and violent; breathing very much inter- 
fered with, on account of the fine snow or frost filling the air. This, 
with the vital depression consequent upon the intense cold, immediately 
lowered the organic life of the atoms in the circulation, and death or 
partial death of these constituent parts of the body took place. Soon 
after the storm-two or three weeks, in some cases-violent efforts of 
the organic life to expel these dying and dead constituents became 
demonstrative. Slight or limited attacks of pleuro-pneumonia of a 
low type, with hemorrhages, became frequent. These were generally 
amenable to treatment, but the interpleural pathological products in- 
creased pari passu afterward with vital depression, and many of the 
sufferers died shortly-that is, within three or four months-with the 
genuine conditions of fibroid phthisis as from depressed organic life. 
The method of death was the same as in that of fibroid phthisis from 
immaterial interior causes; the spirit acting upon the intelligence 
causing the disease and death of the atoms of the body in the tissues 
and in the circulation. Great and prolonged sorrow, deep disappoint- 
ment, worry, and anxiety-the loss of friends and property, of position, 
reputation-always cause death of molecules, which being crowded 
out of the circulation, interpleural pathological products occur which 
may finally result in progressive fibroid phthisis. When this happens 
to a wife or husband who has unduly and inordinately mourned the 
other's loss, it has been ascribed, without sufficient reason, to contagion. 
The known cause of immaterial vital depression through the conscience 
is enough to account for the morbid phenomena, without referring to 
the principle of contagion, of which we know so little. 
I have not known of a case of fibroid phthisis in which a distinct 
history of vital depression could not be elicited by getting the history 
of the mental conditions of the patient during the preceding years. 
Sometimes it comes from great sorrows and anxious worry of a few 
months. Again, it is the result of years of continual unsuccessful 
struggle in the battle of life-the inability to cope with its great dif- 
ficulties. Morbid products accumulate in living organisms. The 
organic life thrusts them out of its dominion, into the pleural cavity, 
for instance, where a feeble reorganization takes place, which con- 
tracts upon the lungs, shutting off* a portion of its circulation and 
crippling its life-power. Here we may notice the great difference be- 
tween these pathological products and those which result from the 
sthenic inflammation. These are characteristic in their morbific re- 
sults, and in this are distinctive of phthisis pulmonalis. It is progres- 
sive-the products are constantly being thrown out into the pleural INTERPLEURAL PATHOLOGICAL PRODUCTS. 
37 
cavity, until the end. One has an inherent tendency to get well, the 
other to die, and needs all the assistance of the physician, or of climate, 
or of food, to arrest its progress. 
Management of fibroid phthisis from interior immaterial causation 
of molecular death, must be rational in order to be successful. The 
organic life expels the diseased and dead particles, crowding them out 
of the circulation. The pleural cavities are generally an ample and 
the most convenient receptacle. The crowded capillaries of the true 
respiratory system are separated from them only by the thin mem- 
brane of the pleurse. As might be expected, the pleural cavities 
give the earliest evidence of morbid impressions upon the individual 
life of the particles or blood-disks. When not overwhelming they are 
thrown out, ejected from the circulation, until the organic life has 
recovered from the attack, and the mass of debris is taken up by 
absorbents and carried out of the system. But if the morbific cause 
continues to operate, more of the waste is expelled from the blood, and 
the pathological products become too much for the absorbents to 
remove; which are soon organized, and commence an independent 
existence. The diseased atoms in this parasitic mass become not only 
mechanically obstructing and depressing, but vitally also, by their 
morbid effect upon the life of the body. Under these great and over- 
whelming difficulties, the mucous membranes of the bronchia become 
exuents through which these dead and dying atoms are expelled in 
the form of mucus, and the broken-down, dying, red corpuscles being 
added to the diseased white ones, a " hemorrhage" results. If we look 
at this state of things wisely and calmly, what are we to do? Attempt 
to resist nature by arresting the "hemorrhage" with ergot, or leave this 
agent to the gynecologist ? For it has no power to arrest a bronchial 
hemorrhage, but rather to increase it; and, if it were possible, it were 
undesirable, for then would be retained in the circulation the morbific 
products which the organic life is endeavoring to expel. 
The most rational, as well as the most successful, remedy, is spirits 
of turpentine applied by frequent washings of the chest externally. 
This has the tendency to prevent or relieve pulmonary stasis: First, 
to remove the interpleural morbific exudates before organization has 
commenced; and, second, to revivify the sick corpuscles, both white 
and red. 
The emergency having passed, we have to deal with organized pro- 
ducts which, by continual contraction, are lessening the area for blood- 
aeration, and progressive emaciation results-consumption. 
Spirits of turpentine is still a valuable agent, stimulating the ab- 38 
INTERPLEURAL PATHOLOGICAL PRODUCTS. 
sorbents and dissipating local congestion, and promoting the health of 
the blood-corpuscles in active circulation. But, above all things else, 
it is important to maintain and increase the area of blood-aeration. 
This is best done by simply breathing rightly, taking in as full respira- 
tion as is comfortable, and then holding the breath in for a short mo- 
ment until the newly inspired air has mixed with the residual air, and 
has expanded under the rarefaction of the blood-heat. This must be 
continuous. It must be the all-time breathing; spasmodic or stated 
periods of correct breathing, of forced inspiration, will not succeed so 
well, for if the expansion is intermittent, the pseudo-membrane will 
recon tract at every intermission, and the fable of Sisyphus will be 
illustrated. For this reason, all mechanical methods of expanding the 
chest, although undoubtedly useful when not violent, are less beneficial 
than correct breathing which is continual. Change of locality, pine- 
woods, and mountain-climbing, may all be beneficial. 
Interpleural pathology has but a casual or accidental connection 
with tubercle. Tubercular inflammation, extending to the pleurae, 
may cause plastic exudation within the pleurae, and occasionally 
tubercle may come independently to the pleural membrane in general 
tuberculosis. And in this connection only will we refer to the bacillus 
tuberculosis, which has come to represent the disease. One thing is 
certain, that wherever a tubercular cavity in the lungs is found, there, 
in the cavity and in the tissues surrounding it, we expect to find in 
great abundance the bacillus. Wherever tubercular concretions or 
aggregations are found, there will the bacilli be also. But sometimes 
as well, but in far less proportion, where there are dead or dying atoms 
from mental anxiety or sorrow, scattered through the body, and, of 
course, in greatest abundance in the lungs, there, too, will be found 
bacilli. In regard to the question of contagion, or specific causation, 
of tubercle, I shall not enter. But in regard to its connection with the 
dead and dying elements within the tissues of the body or in the circu- 
lation of the blood, I have come to no conclusion, except that the con- 
nection is casual, just as mould comes to decaying animal tissues by 
natural selection. And mould and the bacillus tuberculosis are sug- 
gestive of each other.