THE FUNCTION 
O F 
The Eustachian Tube, 
IN ITS RELATION TO THE 
RENEWAL AND DENSITY OF THE AIR IN THE TYMPANIC 
CAVITY, AND TO THE CONCAVITY OF THE 
MEMBRANA TYMPANI. 
B Y 
THOS. F. RUMBOLD, M. D., 
SAINT LOUIS. 
ST. LOUIS: 
SOUTHWESTERN BOOK AND PUBLISHING CO., 510 WASHINGTON AVENUE 
i873- THE FUNCTION 
O F 
The Eustachian Tube, 
i 7 
IN ITS RELATION TO THE 
RENEWAL AND DENSITY OF THE AIR IN THE TYMPANIC 
.CAVITY, AND TO THE CONCAVITY OF THE 
MEMBRANA TYMPANI. 
B Y 
THOS. F. RUMBOLD, M. D., 
SAINT LOUIS. 
ST. LOUIS: 
SOUTHWESTERN BOOK AND PUBLISHING CO., 510 WASHINGTON AVENUE. 
i873- Entered according to Act of Congress, in the year 1873, by 
THOS. F. RUMBOLD, M. D., 
In the Office of the Librarian of Congress, at Washington. PREFACE 
The method of supplying air to the middle ear, the density of 
this air, and the cause of the uniform concavity of that portion of 
the membrana tympani from which is reflected the “ light spot,” 
for some time seemed to have been settled. In calling this in ques- 
tion, it has not been without great misgivings as to my ability to ad- 
duce sufficient reasons to establish the Propositions given. My ex- 
perience in the observations of the phenomena accompanying the 
normal and abnormal conditions of the ear has been comparatively 
so limited that I dread to contrast it with the learned and 
matured opinions of such eminent authors as Toynbee, Helmholtz, 
Troltsch, Hinton, Roosa, and others; and were it not for the con- 
viction that I have facts—all of which have been repeatedly tested 
during the last five years—that seem to support what I have to say, 
I would not presume to dispute their opinions on this subject. 
1205 Washington Avenue, St. Louis, May, 1873. FUNCTION OF THE EUSTACHIAN TUBE. 
In the years 1868 and 1869 I had frequent opportunities of ex- 
amining the symptoms and phenomena of several cases afflicted with 
patency of the eustachian tube, which led me to conclusions that are 
in almost direct opposition to the opinions entertained by Otologists 
of. the present day on the following subjects, viz.: 1st, the method 
of supplying air to the tympanum; 2d, the density of the air within 
this cavity; and 3d, the cause of the* uniform concavity of the 
membrana tympani. 
I will endeavor to prove the correctness of the following Proposi- 
tions, viz.: 
1 st. That during the act of deglutition the eustachian tube is not 
an open passage into the tympanum. 
2d. That the walls of the eustachian tube are constantly in slight 
contact. 
3d. That the air continually permeates the eustachian tube into 
the tympanum, thus maintaining the normal air density in this 
cavity. 
4th. That the air in the normal tympanic cavity is not of equal 
density with that of the surrounding atmosphere, the air in the tym- 
panum being rarefied. 
5th. That one of the functions of the eustachian tube is the 
maintenance of this normal air density. 
6th. That the rarefied condition of the air in the tympanum is 
the cause of the uniform concavity of the membrana tympani, espe- 
cially that portion of it from which the “light spot” is reflected. 
It is not my intention to take up these Propositions seriatim, but to 
give a few of the cases alluded to as they occurred in practice, and 6 
The Generally Accepted Theory. 
the results of the experiments and observations on them, that caused 
me to come to the above conclusions, and afterwards to cite experi- 
ments and additional cases for their substantiation. 
The generally accepted theory of the method of renewing the 
air in the tympanum—first promulgated by Mr. Joseph Toynbee, F. 
R. S., in 1853—is, that the walls of the eustac'nian tube are in con- 
tact when at rest, but that they are drawn apart by the tensor and 
levator palati muscles at every act of deglutition to such an extent 
that the “ air can either enter or recede from the tympanic cavity,” 
thus maintaining a tympanic air density equal with the surrounding 
atmosphere. The proof that is given in support of this theory, is the 
fact, that the act of deglutition relieves the prominent symptoms, 
and the main disability to the hearing that is occasioned by the in- 
flation of the tympanic cavity. This will be designated as the “ deg- 
lutition method ” of tympanic air renewal. 
We cannot make experiments on the eustachian tube, by instru- 
mental means, without incurring some risk of doing injury to this 
important organ ; but this passage is sometimes abnormally open, at 
others abnormally closed. On such occasions we have opportuni- 
ties of judging the effect of these conditions upon (a) the air density 
in the cavity and (h) the concavity of the membrana tympanr 
Both of these conditions of the eustachian tube are very favorable 
for this investigation, as they can be temporarily overcome, so that 
the hearing may be increased equal to or beyond the patient’s 
usual acuteness. 
The phenomena observed during the patent condition of this pas- 
sage, if carefully examined, demonstrate certain facts that appear to 
question the correctness of the “ deglutition method ” of supplying 
air to the middle ear. 
I think that this abnormal condition of the eustachian tube, espe- 
cially in its mild form, is not so rare as might be supposed from the 
infrequency of its mention in our works on the “ Ear,” but rather 
that it is rarely recognized when presented. Even when the patients 
mention the symptoms—if not in an aggravated form—it may at 
once be set down as a case of tinnitus aurium presenting one of its 
many peculiar characteristics, and so passed, for the time, without 
special examination, as has occurred in my own practice on three Case I.—Patent Eustachian Tube. 
7 
known occasions, although at the time I was extremely anxious to 
have such cases for observation, to carry on my investigations of the 
subject that is now under discussion. 
The prolixity of the cases now to be cited will be justified by the 
information they will give upon this subject of increased resonance 
of the patient’s voice in their own ears. 
I take it that the following conclusion is self-evident, to-wit: If the 
eustachian tube is opened into the tympanum by the tensor and 
levator palati muscles, for the normal ventilation of this cavity, at 
every act of deglutition; then any cause that might open this tube, 
aside from the action of the muscles mentioned, would not, on ac- 
count of this opening, be a cause of great disability to the organ of 
hearing. 
From the symptoms accompanying the following cases presenting 
autophony, it is expected to prove that the mere opening of the 
eustachian tube, for a short or long period of time, is a cause of too 
great disability to the organ of hearing to admit of its being open 
during the act of deglutition without producing some of the same 
disturbing phenomena; and that, while the eustachian tube is in a 
patent condition, the membrana tympani is less concave than normal. 
Case I.—Feb. $th, 1868.—Otto Z , German, aged about 38 
years, farmer, from Columbia, Mo., applied to be relieved from ex- 
cessive noise in his left ear while talking. He had been deaf in this 
ear since 1862 ; he supposes that it was occasioned “ by long expo- 
sure in the woods.” His right ear proved, upon examination, to be 
also affected. This phenomenon in the left ear first appeared eight 
days ago, and with it considerable increase of deafness and a sensa- 
tion of fullness, or as if he had something in the ear. He hears his 
voice in this ear first. It would not be exactly correct to say that 
he heard all of his words at. separate intervals, but they lap one upon 
another, producing quite a confusion of sounds. When pronouncing 
one short sound quickly, as “ah,” through the nose, there was no 
lapping, but two sounds, one following the other in instant succes- 
sion ; the first sound in a strong, hollow, deep tone immediately in 
this ear; the second one in the ordinary tone, and heard from with- 
out. Several nights ago he was awakened from sleep by a blowing 
sound in this ear. 8 
Case I.—Experiments With. 
On inspection of the membrana tympani of the left ear, the con- 
cavity was found to be slight. I will remark, that the curvature was 
not so remarkable for shallowness as to attract my attention even for 
the first two days of examination. It was not until I had made up 
my mind that the tube was abnormally open that I noticed the 
great contrast between this, and that of the right ear. The hearing 
distance with the watch (normal hearing distance about 120") with 
right ear was 36", left, on slight pressure. On examination of the 
pharyngo-nasal cavity, it was found occupied by a large accumula- 
tion of offensive muco-purulent secretion, the whole mucous mem- 
brane being affected with a chronic inflammation. The mouth of 
each eustachian tube was quite large, they also partaking of the 
same general congestion. 
While examining his case he twice asked me if I could not hear 
him talk through the left ear; the sound of his voice in this ear was 
so loud to himself that he thought others must hear it also. 
The posterior nares syringe was used with warm salt water (3j-Oj) 
to clean out the offensive secretion above and behind the soft palate. 
The first injection washed out a large quantity of this matter. After 
the recovery from the choking sensation occasioned by the injec- 
tion, he found, upon answering a question, that the sound of his 
voice in the left ear had disappeared. It required nearly one quart 
of water to clear out the pharyngo-nasal cavity. 
Feb. 6th.—The sound of his voice in the left ear was absent for 
nearly two hours after the last treatment, returning after he had used 
his handkerchief to blow his nose. The posterior nares was again 
washed out, using about half a pint of warm salt water. The first 
syringeful again stopped the phnomenon. 
Feb. —The sound of his voice in this ear did not return for 
three hours after the last treatment, happening this time without any 
known cause. Last night he was again awakened by the blowing 
sound in this ear; this is still present. As the patient insisted on 
my listening to it, I took the aural auscultating tube* and placed it 
in this ear. With the aid of the instrument, I found to my great 
surprise that the blowing sound was occasioned by his respirations. 
* I consider this a preferable name to that of “ otoscope,” or “diagnostic tube,” 
being more descriptive of the use of the instrument. Case I.—Hearing His Respiration. 
9 
It was much more distinct when he breathed through his nose with 
his mouth closed, then it sounded somewhat like blowing over the 
mouth of an old-fashioned ounce bottle; when his mouth was open 
it could not be heard so distinctly; and when he breathed only 
through his mouth it was not heard at all. His voice, as heard 
from his ear, while not near so loud, had the peculiarity of the hol- 
lowness and proximity that can be illustrated by placing the stetho- 
scope near the larynx. 
After one injection of the warm salt water, all the peculiarities of 
the case weredost, but were made to return again—except the hear- 
ing of the respiration—by the repeated blowing of the nose. The 
aural auscultating tube was again applied to this ear, and the previ- 
ous observation confirmed. Another douche with the syringe again 
shut out the sounds, but were caused to return by more blowing 
of the nose. Politzer’s air douche was not used for fear of injuring 
the membrana tympani thus exposed. 
Feb. &th.—The relief from hearing his voice in this ear lasted 
until he fell asleep. On awaking this morning he found the symp- 
toms the same. Says that the upper and posterior portion of his 
throat is somewhat painful, and that his hearing is not quite so good. 
Watch heard in right ear, 30 ", in left same as before stated. The 
same examination with the aural auscultating tube, and the use of 
the syringe, fully confirmed yesterday’s observations, the only differ- 
ence being that it required greater exertion on the part of the patient 
to clear the tube after it was filled with water. 
Feb. 10th.—The patency did not return until yesterday morning, 
being absent about twenty-four hours. Has more pain in the head 
than usual; tinnitus in right ear; hearing in this ear 28 ". Accord- 
ing to directions, yesterday he snuffed warm salt water into his left 
nostril, while his head was inclined to that side. After repeated 
efforts, this had the effect of shutting off the sound of his voice from 
this ear, but the relief was not of long duration. The same examina- 
tion with the aural auscultating tube, followed by the use of the pos- 
terior nares syringe, was repeated to to-day as often as the eustachian 
tube could be cleared of fluid by blowing the nose, confirming all 
that was before observed. 
Feb. n th.—The tube did not open until about ten o’clock last Observations on the Membrane. 
10 
night. This morning he was successful in forcing water from his 
mouth up behind the soft palate into his nose, while his head was 
inclined to the left side. This stopped the sound of his voice in this 
ear, lasting for an hour or two, or until he coughed or blew his nose, 
when he could again stop the sound of the voice with more water. 
This plan of experiments and observations was continued every 
other day until the 24th of February, at which time the autophony 
was permanently shut off. This was apparently brought about by 
the application of a grs. x solution of argenti nitras to the mouth of 
the left eustachian tube, by means of a sponge, and held there about 
two seconds. 
On the 2d of March he could hear the watch with this ear when 
it was just away from contact, on the 6th when y2 " from it. The 
membrana tympani was now more concave, and the “ cone of light ” 
smaller and brighter (6th Proposition). The hearing with the right 
ear on the 6th of March, 34 Although this is two inches less than 
when he first presented himself, yet he claims that he can hear very 
much better, especially that he is not so much in doubt as to the 
direction that sounds come from. 
After the experiments and observations on the 7th of February 
(1868), I considered that the case had demonstrated itself to be that 
of an abnormally open eustachian tube, and then conceived the idea 
that it was necessary to have this passage constantly closed for nor- 
mal hearing. Soon after this my doubtful opinion was converted 
into almost positive conclusions by finding that Mr. Toynbee made 
a mistake in his first experiment, given to prove the correctness of 
his theory; * also that he was in error in the diagnosis of his cases 
of this same class, reported on page 155 of his work. 
Case II.—About the latter part of March, 1868, I noticed my 
friend, Dr. Charles K , of the firm of A. M. Leslie & Co., of this 
city, close his nostrils with his thumb and forefinger, instantly mak- 
ing an inspiratory effort while his mouth was also closed. The rea- 
son for this procedure instantly came into my mind. I made the 
remark to him at the time, that he abstracted air out of his tympanic 
cavity to drive away a disagreeable fullness in the ear, and prevent the 
* Tovnbee on “Diseases of the Ear,” page 192. Case III.—Experiments With. 
11 
sound of his voice from reaching it, and also to increase his hearing. 
He replied that I was right, stating that he was frequently (may be 
forty to fifty times through the day) compelled to do so after taking 
a cold in the head, which he was very subject to. Not long after this 
I had an opportunity of examining his right ear (the one affected), 
and found that previous to the abstraction of air from the cavity the 
membrana tympani was but slightly concave, the “ light spot ” and 
whole surface dull; but as soon as he made a quick inhaling effort, 
with mouth and nose closed, the dullness disappeared, the concavity 
was increased, and with this change the removal of the sensation of 
fullness in the ear, the muffled, deep sound of his voice, at the same 
instant the increase of his hearing for outside sounds. (4th, 5th, 
and 6th Propositions.) 
February 8th, 1872, he informed me that at one time, when greatly 
troubled with this autophony, he used Politzer’s air douche with im- 
mediate though not lasting benefit. 
Case III.—-The next case of this character that came under my 
observation was (Jan. 8th, 1869,) Mrs. Mary E. T , aged about 
28 years. She was also a patient of Dr. M. A. Pallen, of this city, 
for uterine disease. Had been, until last year, a school teacher. 
Her hearing in the left ear has been affected for about five years; 
in the right, about one year. 
The interesting symptom in this case was the direct transmission of 
her voice through the left eustachian tube to the left ear. This could 
be considerably increased by yawning, at the same time breathing out 
through the nostrils; while in this condition, with the aural auscultat- 
ing tube introduced into this ear, the deep, hollow sound of the voice 
could be easily heard. All deep tones were much more manifest. 
The “ing ” in pronouncing “ morning ” was very distinct. 
On the 19th of January the eustachian catheter was introduced 
well into the mouth of this tube; with the aural auscultating tube it 
was noticed that the sound of her voice was nearly shut off, but the 
flapping or purring sound of the catheter was very marked, seeming 
right in my ear. After an inflation by this means, she noticed that 
she could, keep the eustachian tube closed a little longer after an in- 
haling effort similar to Dr. K.’s. 
After injecting warm water, having a little slippery elm dissolved 12 
Hearing Increased by Rarefaction. 
in it, into the left nostril, while the head was inclined to that side, 
the sound of her voice was shut out from her ear for several hours. 
When the eustachian tube was patent, so that her voice could be 
heard through it with the aid of the aural auscultating tube, the 
“ cone of light ” was broad and dull in luster, but instantly, on per- 
forming the act of deglutition with the nostrils closed, especially on 
making a quick inhaling effort, it became smaller and brighter, prov- 
ing conclusively an increase of the concavity of the membrana tym- 
pani by rarefaction of the air in the cavity and closure of the eusta- 
chian tube : at the same instant the hearing of her voice, abnorm- 
ally, in this ear was cut off, but the hearing of external sounds in- 
creased. 
I might relate a few other cases having the same phenomena that 
have come under my observation, but will only add the following 
two, viz.: 
Case IV.—Rev. Dr. B. F. C., of this city, aged about 50 years. 
About nine years ago his left ear was injured by an unexpected dis- 
charge of a cannon near him. Three years ago Dr. A. S. Barnes, 
of this city, recommended him to consult me about the ear. On 
examination of the membrana tympani it was seen to be very con- 
cave, the “ bright spot ” quite small, showing that the eustachian 
tube did not allow sufficient air to pass into the tympanic cavity; 
the pharyngo-nasal space was found to be affected with chronic in- 
flammation of the mucous membrane. For this he received a long 
course of treatment, but with indifferent success. 
On Jan. 24th, 1872, he consulted me for a directly opposite dis- 
ease of the eustachian tube, that of patency—hearing his voice ab- 
normally loud in this left ear. This was apparently occasioned by a 
severe cold in the head. His voice sounded to him as though it 
was immediately in the ear, and seemed double, or as though some 
one was talking just back of his left ear. This was so very annoying 
that he could not think with freedom while speaking. On one oc- 
casion he was compelled to desist from preaching on account of it. 
Accompanying this, was fullness in the ear and increased dullness in 
hearing. 
With the aural auscultating tube the peculiar sound of his voice 
could very easily be heard. The greatest contrast between any two Cases IV and V.—Experiments. 
13 
sounds heard from this ear was that of “ a” and “ing; ” the former 
could scarcely be heard; the latter was remarkable for its penetrat- 
ing power to my ear. 
Strong pressure on the tragus, closing the auditory meatus, de- 
creased the autophony, but did not entirely check it. For the purpose 
of ascertaining whether or not it was the mere pressure that caused this 
disappearance, I had him press equally as strong into the meatus the 
end of the aural auscultating tube; this had no effect whatever upon 
the autophony. I then placed a piece of sheet rubber over the end 
of the tube and pressed as before; this had the same effect as the 
finger. These experiments were repeated several times with the same 
result. 
Two drops of warm salt water placed into the auditory meatus 
(preparatory to the application of the constant current of electricity 
for the treatment of the disease) had no apparent effect in checking 
the phenomenon ; three drops more decreased it a little. When 
the canal was about half full there was still a little resonance on 
phonation ; but when it was as full as it could hold, there was none 
at all.* This experiment was not repeated. The electricity removed 
every symptom of patency for several days, and when it returned it 
was so slight that I could not hear his voice at all from the ear. 
Case V.—March 27th, 1872.—Miss Mollie K , of this city, 
aged 19 years. She has had perforation of both membranse tym- 
pani and otorrhcea in both ears since she was a small girl. The fol- 
lowing are the symptoms of her autophony, in her own words, viz.: 
“ I have had breathing in my right ear many times during the last 
winter, and up to the present time, each attack lasting sometimes an 
hour or two. At such times I have but little matter in my ear, and 
feel as though something had moved away; then I hear the sound 
of my breathing. I always drive this away by syringing my ear 
with luke-warm water. It is such an unsufferable feeling that 1 have 
to keep washing out my ear until it stops. As soon as the water 
stops going into my throat, then I know that the sounds will stay 
away.” 
* These two experiments on this and the following case were suggested by 
reading Dr. Brunner’s article, in the Arch. Opht. and Oto., Vol. II, No. X, page 
no. 1871. 14 
Patent Tube and Perforated Membrane. 
Question.—What does the noise in your ear resemble ? 
Answer.—“ It sounds like a very loud breathing in the head, 
striking the ear drum quite hard; and, if 1 speak, it sounds as if I 
were in an empty room, and as though I heard the echo of my voice. 
It is not the voice that comes from my mouth that hurts and sounds 
so loud in my ear, but that part of it that goes to my ear from my 
throat. The voice that comes from my mouth sounds last, and is 
like the echo in the room. I never speak loud at those times, be- 
cause it hurts the ear drum and causes my head to ache very bad.” 
Ques.—What is the condition of your ear when this occurs ? 
Ans.—“ It occurs at a time when I have a very bad cold in my 
ear, and when it is not running; at the same time my nose is hot 
and dry. My breath coming from my ear into my throat is very 
offensive.” 
Ques.—Is your hearing more difficult at such times ? 
Ans.—“ No; I hear as well at any time; sometimes I think that 
I hear better.” 
Ques.—Have you ever tried to stop this unusual sound of your 
breathing by closing your ear with your finger, or anything else ? 
Ans.—“ Oh, yes ; but that does no good; it only keeps me from 
hearing other persons.” 
Ques.—Did it not stop the noise a little, and make you feel a little 
better ? 
Ans.—“ Not in the least [with emphasis]; nothing but something 
run away into my ear would do any good. Sometimes, after washing 
my ear with water, the sounds would [after being away] soon begin 
to return, then I have wet the cotton with glycerine and put this in 
it, if I felt it [the resonance] coming on I would squeeze the cotton 
a little, so that some of the glycerine would run farther into my ear; 
at the same time I would hold my head on my left shoulder; then 
the breathing sounds would stop.” 
The important facts observed during the pathological stage of the 
first three cases, and sustained by the fourth, that I wish to be kept 
prominently in view, are as follows, viz.: a, sensation of fullness in 
the ears; b. decreased hearing; c, increased resonance of voice in 
the ear affected; and d, decreased concavity of their membranae 
tympani, all occasioned by the eustachian tube being open. Now, Mr. Toynbee's Cases. 
15 
there is no disputing but that the air densities on both sides of their 
membranae tympani were equal; therefore, according to Toynbee and 
Troltsch, this condition of the eustachian passage ; of the tympanic 
air density; and of the curvature of the membrane—because it was 
a consequence of the others—should not have given rise to so great 
a disability in their hearing; because they insist that these conditions 
are in accordance with the physiological functions of the ear. 
To show that preconceived opinions have not biased my obser- 
vation of these cases, a few more of the same class will be placed 
before the reader, which were observed and reported by Aurists whose 
opinions of the cause of the phenomena attending them are entirely 
at variance with those presented in this paper. The first that will 
be given are three mentioned by Mr. Toynbee. The close resem- 
blance of the prominent symptoms to those cases just related are 
very manifest. They are found on page 155 of his valuable work 
on the “ Diseases of the Ear,” under the head of “ Relaxation of the 
Fibrous Laminae of the Membrana Tympani.” He states that “The 
causes of this are—1st, the effects of an ordinary cold, producing 
hypertrophy of the mucous layer; 2d, inflammation of the fibrous 
layers. From either of these causes the membrana tympani may 
lose its natural resiliency, and become flaccid, so as to fall inward and 
approach more nearly the promontory than is natural.” 
I wish to remark, in advance of the comparison to be instituted 
between his theory of the cause of their disability in hearing, and 
the facts which are developed by the history of his cases, that it is 
not possible for the membrana tympani to fall uiward because of 
any degree of relaxation. It is well known that its inclination is 
such that the upper margin is 6 mm. nearer the external orifice of 
the ear than the lower. It is evident that every movement made 
in the direction of the promontory is really an upward instead of a 
downward one, and that relaxation with equal air densities on both 
of its sides—as did exist in those cases—would not cause it to take 
that direction. 
His description of the state of the membrana tympani of his first 
case, is strong proof that the concavity was at its minimum, for he 
states that the “ bright spot [ is ] elongated.” Another evidence of 
the patency of the eustachian tube of this individual, is that the act 16 
Hearing Increased by Rarefaction. 
of deglutition, performed with the nostrils closed, relieved the disa- 
bility (4tl\ Prop.), lasting until the same act was performed with the 
nostrils open, which, with this patient, again gave rise to patency and 
its consequences. 
With his second case, “ the bright spot [of the membrane is] much 
larger than natural,” which is strong evidence that its concavity was 
as nearly flat as the traction of the tensor tympani would allow it to 
assume. “ The rumbling sensation and the deafness are both tem- 
porarily relieved by suddenly and forcibly drawing in the breath 
through the nostrils.” (4th, 5th, and 6th Props.) Here the hearing 
was increased by closing the patent eustachian tube, at the same 
time abstracting air from the tympanic cavity, and causing the in- 
creased concavity of the membrana tympani in a manner exactly 
similar to some of my cases. He adds, that “ The patient has thus 
acquired the habit [?] of incessantly snifflng the air, which is exceed- 
ingly unpleasant to himself and to every one around him.” 
In the history of his third case he has not been as explicit in his 
description of what he saw, or the method taken by the patients for 
relief; but taking into consideration its connection with the other 
cases, and his using the same expression concerning the method 
employed for temporary relief, there is evidence enough to consider 
it to be similar in character. In the latter part of the history of this 
patient, he states “ the healing remained mucn better, except during 
attacks of cold, when the old habit-of clearing the ears, by forcing 
air into them, was had recourse to.” It is evident that the habit of 
“ clearing the ears ” is similar to those of his other cases, notwith- 
standing he calls it forcing air into them. 
This examination of the history of his cases readily proves that he 
was mistaken (a) in the direction that the membrane took when he 
instructed them to perform the act of deglutition with their nostrils 
closed, as this must cause it to rise and approach the promontory, 
instead of, as he supposed, forcing it outward and away from it; (b) 
consequently, in error as to the cause of the disability in their hear- 
ing : and (c) in his theory that, for normal hearing, the air density 
in the middle ear must always be equal with the surrounding atmos- 
phere. Comparing Mr. Toynbee's Theory With Facts. 
Let us compare the facts, as observed in his cases, with his 
theory: 
He says that the eustachian 
tube must be opened at each act 
of deglutition for normal hear- 
ing. 
He says that the air in the 
tympanic cavity must “ be al- 
ways of the same density as the 
outer air.” 
They find that every time that 
it is open the hearing is decreased, 
(ist Prop.) 
They are compelled to abstract 
air (4th Prop.) for the purpose of 
increasing the concavity of their 
membranae tympani (6th Prop.), 
to increase their hearing, and ddso 
for the purpose of closing the 
eustachian tube. 
Again, while the eustachian tube remained closed (2d Prop.), the 
increased concavity of the membrana tympani remained stationary 
(5th Prop.). Now, as this condition of the tube and the membrane 
is continuous, upon the permanent recovery of the patients, and as 
there is a process of air exhaustion going on in the middle ear, also 
continuous, therefore, if the hearing remains uniform, it proves the 
I 
continous reception of air to the middle ear. (3d Prop.) 
While it is evident that the traction of the tensor tympani upon 
the manubrium accounts in a great measure for the concavity ol the 
membrana tympani, it is seen that the facts observed in those cases 
prove that it does not maintain its uniform concavity, especially that 
portion of it from which is reflected the “ light spot; ” and that this 
condition is maintained by the excess of outside air pressure, as com- 
pared with that on its internal surface. When this excess was not 
present, the membrane assumed as flat a form as its attachments 
will allow it to take; that is to say, that the unassisted traction of 
the muscle named maintains it in the same form that a cone, if 
pressed against it, would do; but the excess of outside air pressure, 
in addition to this traction, maintains it in a condition that a ball 
would do if put in the place of the cone; so that a section of the 
membrane, passing through the umbo, would present a curved line, 
not an angle. 
The next case of this class that I will quote, is taken from the 
“Archives of Ophthalmology and Otology,” Vol. II, No. 1, page 18 
Dr. Brunner's Case—Gruber's Theory. 
i°7 (x87x), reported by Dr. Gustav Brunner, of Zurich, Switzer- 
land. 
This case is given in support of the theory, that the closed eusta- 
chian tube, assisted by bone conduction—not fluid in the middle 
ear, as claimed by Gruber—is the cause of the increased resonance 
or autophony in this patient. 
As I wish to employ this illustrative case to prove that it was an 
opposite condition of this passage, I will be compelled to criticise 
his conclusions, while accepting the results of his ingenious experi- 
ments upon his patient. 
His case was a female, “ 45 years old. Had become deaf after 
having catarrh the whole winter, but had never before had any trou- 
ble with the ear. In April, 1870, sudden pain in right ear, without any 
distinct history of taking cold.” “ She now does not 
complain of any particular pain, but a feeling of stoppage of the 
right ear; particularly, however, that her own voice resounds very 
strongly in the right ear in such a manner that speaking is very dis- 
agreeable to her; even her own respirations sound so loud and sibi- 
lant as to be troublesome. She also hears every motion of the jaws 
with unusual distinctness.” . . . “By auscultation with the 
otoscope one perceives quite a difference between right and left ear. 
On the right side the voice of the patient sounds uncommonly loud 
and hollow, with a tremulous continuation of tone ; speech even in 
common conversation, as though one was speaking in a vaulted 
chamber or in a long speaking tube, and, on raising the voice, the 
sound is reduplicated; in quiet breathing, sound through the oto- 
scope remarkably loud and sibilant.” . . . “ I introduced 
the catheter on the right side and blew air in by means of the air 
bag, when I heard a strong roaring or blowing upon auscultation, 
which made, in spite of its intensity, the impression of a distinct 
noise arising from the palate, or, at most, from the mouth of the 
tubes." 
“ The air douche was without permanent influence upon the phe- 
nomena. I now made, in view of Gruber’s assertion — although 
from the result of the examination of the membrana tympani the 
presence of liquid in the tympanic cavity was not at all probable—a 
small perforation into the right membrana tympani.” Patency of the Tube Proved. 
“ The autophony was not altered by this proceeding, and no air 
issued from the opening, in spite of strong and repeated douches of 
air through the catheter (the tube was, no doubt, still closed). As 
soon, however, as the air, after repeated efforts, passed through the 
opening in the membrana tympani with an audible hissing sound, 
the troublesome resonance, both subjective and objective, disap- 
peared, as if by magic, and did not return when I injected a weak 
solution ot zinc by means of the catheter.” 
“ I remarked particularly that not the slightest secretion made its 
appearance through the membrana tympani. Now the air passed 
whizzing through with great ease by the patient’s simply blowing the 
nose, and the improvement continued until next morning. In the 
evening, however, the patient was no longer able to force any air 
through the membrana tympani.” 
“ When I saw her two days afterwards the opening was closed; 
no reaction had followed the paracentesis, but the group of trouble- 
some symptoms were present as strongly as before. State of the 
membrana tympani same as in the beginning.” 
“ . . . . this time the air douche availed nothing. Only 
after I had blown in some solution of zinc the resonance of the voice 
suddenly disappeared, and remained absent till the next morning. 
(To me this observation, which I subsequently repeated, is explained 
as follows: that after the moistening of the collapsed walls of the 
tube the stream of air more easily finds admittance.) Two days 
later the patient presented herself again. The autophony continued 
with unabated violence. Repetition of the air douche was of no 
use, and even the injection ot fluids at this time proved negative.” 
If his theory of the cause of the disappearance of the autophony— 
that is, by opening the tube—is correct, would it not be a more suc- 
cessful method to introduce and retain a catheter in the eustachian 
passage, as recommended by Dr. Jago, to prove patency ?* Is it 
not more reasonable to suppose that the water occupied all of the 
free space in this small and narrow passage that it would in any 
opening of the same size and shape, and, while remaining there* 
would act as an obstruction to the passage of sound in a manner 
* Jago on the Eustachian Tube.—British and Foreign Medico-Chirurgical Re- 
view, January and April, 1867, page 181. 20 
Bougie and Fluid Experiments. 
precisely similar if it had been injected into Dr. B.’s aural auscultat- 
ing tube while he was examining the ear with it ? The following 
quotations also plainly show that this view is correct, viz.: 
“ The patient states that the air began to pass into the ears, but 
was suddenly interrupted. I now pushed a bougie of about i 
mm., in thickness through the catheter. At the middle of the tube 
it was arrested, and could not be carried any further; but the auto- 
phony had now disappeared. If I pulled the bougie back a little 
the symptoms reappeared, and disappeared again when the bougie 
was introduced. Thereupon, I took quite a thin bougie, 
mm., which was also arrested at the spot mentioned, and found great 
resistance, but at last entered the cavitas tympani; whereupon, the 
autophony ceased, even with the otoscope.” 
“ I usually injected a solution of zinci sulphas (grs. iij, 3j), and 
I remarked particularly that the injected liquid never produced 
autophony; on the contrary, it disappeared, as I observed above, 
sometimes not from the effect of the air douche, but by blowing in a 
few drops of liquid,.” 
% . 
“ Violent sneezing would sometimes bring on autophony, as also 
merely stooping, whilst co7itinued gargling often caused it to disappear. 
When the autophony is absent the patient feels much more comfort- 
able, and says she hears better, although with the watch no marked 
difference can be noticed.” 
Such an array of symptoms, all pointing plainly one way, namely, 
that she heard the sound of her voice through an unusual avenue to 
her ear, is not to be excelled, even in the history of Dr. Jago’s case, 
related of himself. Yet he repeats, on page 117, “ It appears to me 
most natural at present to seek the cause of its frequent alternations in 
a stoppage of the tubes.” 
“ That such really existed is shown by the result of the ausculta- 
tion, and by the fact that the solution of zinc injected through the 
catheter never or seldom occasioned any burning in the ear.” 
I think that it is not necessary to spend much time in criticising 
his conclusion, that the auscultation demonstrated stoppage of the 
tube, for the quotations already given state, as plainly as can be, 
that he heard with the aural auscultating tube introduced into her 
ear. “ On the right side the voice of the patient sounds uncom- Difficulty of Injecting Open Tubes. 
21 
monly loud and hollow,” . . . . “ in quiet breathing sounds remark- 
able loud and sibilant; ” and the sound from the catheter gave “ the 
impression of a distant noise arising from the palate, or at most from 
the mouth of the tube.” Even if he had desired to describe the 
symptoms of patency, as proved by this phenomenon, observed dur- 
ing this experiment, he could not have used more expressive or 
descriptive language. 
The history of this case will suggest, upon reflection, that the rea- 
son that the injection of the zinc solution did not reach the cavity 
of the tympanum, might not have been on account of closing of the 
eustachian tube, but, on the contrary, because of its being too open. 
I consider that the fact of his inability to successfully inject the solu- 
tion into the tympanic cavity of this patient, is another evidence of 
the correctness of my opinion—that is, that this case had an abnor- 
mally open eustachian tube, so that “ air could either enter or recede 
from the tympanum.” 
Evidently, if the tube had been long closed, there must have been 
rarefaction of the air in the tympanum by absorption; therefore, 
just as soon as equalization of the air density transpired upon the 
opening of the tube by the injection, the liquid must of necessity 
have been forced into the cavity by atmospheric pressure at the 
same moment, or before the air entered it. 
I am free to affirm, that it is almost impossible to force a liquid 
into a long, narrow tube, similar to the one under consideration, 
with one of its extremities closed, because of the condensation of 
the air in the further extremity of the tube, by this procedure; and 
that the only method by which a fluid can be made to enter such a 
passage with facility, is, as is found in long-closed eustachian tubes, 
by a rarefied condition of the air in the tympanum, occasioned by 
absorption. I mean by this, that it is not probable that a fluid can 
be injected into a tympanic cavity having a patent eustachian tube, 
and an imperforate membrana tympani, because the air already in 
the tympanum and the tube—which cannot be condensed—has no 
avenue for escape, the tube being too small in caliber to allow the 
liquid to enter and the air to come out at the same time; but if 
there had been a perforation of the membrana tympani, then there 
would have been no difficulty in injecting the solution into the tym- 22 
Hearing Increased by Rarefaction. 
panum, for the air in the cavity could and would escape through 
this opening in the membrane. 
He gives other reasons in the support of his theory, that the ab- 
normally closed tube always accompanied this autophony, but the 
only one I will mention is found on page 118. Its ingenuity and 
seeming correctness call for attention. He says : “ It might seem 
strange that tympanophony did not appear during the introduction 
of the bougie, but we shall cease to wonder at this when we con- 
sider that the tube is not a round, but a fissure-shaped canal; the 
bougie cannot, therefore, fill up the whole cavity, but will act as a 
wedge, holding the walls asunder.” 
Keeping in mind the comparative dimensions of this “ collapsed- 
tube ” shaped passage and the bougies, I think that it is a little doubt- 
ful that even the larger one would act as a wedge, holding the walls 
above it or below it sufficiently apart for the sound of her voice to en- 
ter, without taking into consideration that at the same time there was a 
constriction—which must have bee?i membranous and nearly circular— 
so great that it could not be made to pass, and the one of if mm. 
required pressure to overcome “ great resistance.” How could the 
sound pass through that part of the tube occupied by this membranous 
and circular constriction, while the larger bougie filled it to its utmost 
capacity ? But we are told that the phenomenon disappeared while 
the bougie was pressing upon this constriction, only occupying the 
anterior half of the tube, leaving all posterior to this unopened. 
There are no facts related here that say the sound from the larynx 
entered the middle ear by this passage under these circumstances. 
On page 115 he gives what must be considered as positive evi- 
dence that there had been no closure of the eustachian tube, but 
the opposite condition, viz.: As the hearing increased “from o to 16 
centimetres,” he says, “ The injection of the membrana tympani has 
disappeared, and it shows instead a grayish cloudiness, and some m- 
crease of concavity—nothing particular.” (4th, 5th, and 6th Props.). 
What could increase the curvature of this membrane ? Facts and 
recognized authority answer, air absorption within the middle ear, 
causing rarefaction. As this air abstraction could not thus effect it 
with an open eustachian tube, it proves a closed one. That this is 
the normal condition of the tympanic air density, is proved by the Dr. Brunner’s Theory. 
23 
fact, that increased hearing was concomitant with the increased con- 
cavity of the membrane and closure of the tube. 
On page 124 he gives his theory of the cause of these phe- 
nomena : 
“ To return to the history of our patient, the reason why only her 
own voice and breathing, but not the sounds produced outside and 
in the air, showed a strikingly louder and changed tone can only be 
that, in the first instance, the source of sound lies in our own body, 
and that besides, the conduction through the outer air, the conduc- 
tion through the solid parts exert an influence. 
“ From this circumstance we must explain the augmented reson- 
ance of the voice. Taking it for granted that complete closure of 
the tubes is favorable to resonance in the drum, it will appear never- 
theless strange that resonance appears only in the sound of our own 
voice, and not likewise in that of others, and we are obliged to seek 
the conditions for this resonance in the conduction of the bones.” 
The effort in these two sentences is to prove that the autophony 
is propagated to the ear by the conductive property of the bones, 
assisted by complete closure of the tube. Indeed, he must consider 
this bone conduction as the greater cause, for he has admitted that 
we have too large a class of cases of obstructed tubes without auto- 
phony to place much stress upon this condition of the passage as 
occasioning these phenomena. 
The property of conduction in any substance is not changeable 
suddenly, but in this case we are forced to say that it was arrested 
in increasing the resonance of the voice, by the air douche, by a few 
drops of fluid injected into the eustachian tube, by gargling, by the 
large bougie that could not, according to his opinion, open the whole 
length of the tube, and by the smaller one that did, after consider- 
able force, penetrate to the cavity, for all of them did cut off the 
increased resonance of her voice. But did they at the same time 
change the conductive power of the bones ? Was not this property 
in them just the same after the resonance had disappeared as be- 
fore ? He says: “ By auscultation with the otoscope one perceives 
quite a difference between the right and left ear.” No one can 
doubt but that the bone conduction must have been equal on both 
sides of the head. 24 
Dr. B.'s Experiments Explained. 
On page no he relates two experiments, viz.: “All these phe- 
nomena, subjective and objective, completely disappeared when the 
right ear was filled with water; the patient’s own voice then sounded 
as usual. This was also the case upon stopping the auditory canal 
by strongly compressing the tragus, but upon opening the auditory 
canal all the symptoms reappeared immediately.” 
I have made the same experiment—only once—on one of my 
patients, who had an imperforate membrana tympani (Case IV, Rev. 
Dr. C.), with the same result. My explanation at the time, and the 
facts seemed to bear me out, was that the column of water inter- 
fered with the vibrations of the membrane, and that this interference 
also occurred from the closure of the auditory canal by the condensed 
air pressing upon the imperforate membrane. It will be remembered 
that pressure, without the means of condensing the air, did not thus 
effect the resonance. It will also be remembered that this patient 
observed that when only a few drops of water were on the mem- 
brana tympani it had but little effect, but when filled the autophony 
was gone. That the glycerine in the auditory canal of Miss K. 
(Case V) should have the effect of stopping the increased resonance 
is not to be wondered at, because it passed directly through the per- 
forated membrana tympani into the eustachian tube, closing the 
avenue for the sound to reach the ear, requiring only two or three 
drops to do this. Strong pressure on her tragus had no influence 
whatever in diminishing the autophony; but with the Rev. Dr. C. it 
had a modifying effect, but only when the canal completely closed 
at the same time.* 
I will now make some quotations from an article written by Dr. 
Jogo, of England. He has contributed two papers upon the subject 
of Patency of the Eustachian tube in the British and Foreign Medi. 
co-Chirurgical Review, one in the January and the other in the 
April numbers, 1867. 
I desire to use these quotations merely for the purpose of showing 
that I am not mistaken with respect to the character of the cases 
just given; that they are, as asserted, those of abnormally open 
eustachian tubes. 
He was afflicted with this very annoying disease, and devoted 
*See foot note, page 13. Dr. jf'ago's Cases. 
25 
quite an amount of time to various experiments upon his ear, and 
carefully noted the symptoms accompanying the disease and these 
experiments. There is not any probability of his being mistaken 
when he says that “ It is now full fourteen years since I have under- 
stood the phenomena which an open eustachian tube entails.” 
I will make the quotations from pages 181, 182 and 183 : 
“ But I am confident that any one who may provide himself with 
a tube open at both ends, just the size to pass through a nostril into 
the throat, and having projecting from it another near one of its 
ends suitable for being passed into the eustachian tube may, by thus 
introducing this into one of his tubes so that the air may pass freely 
from it into the drums, verify all my main experiments.” 
“ In proof of this explanation I may adduce that, whenever I have 
been teased by the patency of the tube, I have always been able to 
close it for some instants by an inspiratory movement, with nose and 
mouth stopped.” (4th, 5th and 6th Props.) 
“ I will subjoin, that in explosive expirations, or in speaking, 
coughing, hawking, sneezing, the pressure upon membrana tympani 
is painful, and in the more violent, particularly involuntary kinds, 
threatened its integrity.” . . . “ Every word spoken whilst 
the tube is open strikes the membrana tympani through it, and is 
thus heard many times louder upon this ear than upon the other. 
The eustachian tube is minute as compared with the external audi- 
ditory canal, and can only admit a fraction of the volume of air 
that the latter holds. And, therefore, I do not mean to affirm that 
my experience of speaking into my own eustachian tube is so stun- 
ning as what happens when another person speaks into the external 
one with his lips applied to the auricle. Yet, the illustration is so 
correct that, with a due allowance for the difference pointed out, it 
will convey a fair idea of the nature of the shock.” 
“ Inspiratory sounds are also heard through the tube, but then 
only in a very faint manner.” 
On page 185 he relates a case similar to his own. “About a dozen 
years ago a young woman, a member of a church choir, with only 
a very slight appearance of faucial relaxation, and a slight elongated 
uvula, with no other sign of ill health than a slight anaemic look, 
narrated symptoms essentially like those before us.” 26 
Patency a Physical Cause of Decreased Hearing. 
“ She had herself discovered and practiced the mode of reducing 
her bulging outward membrana tympani by trying to breathe with shut 
nose a?id mouth." (4th, 5th and 6th Props.) 
Were it not for the rare description of this disease of the eusta- 
chian tube, either in our Books or Journals, a less amount of space 
and a less number of cases would have sufficed to prove all that was 
undertaken, namely, that the mere opening of the eustachian tube 
into the tympanum is a cause of too great a disability to the organ 
of hearing to suppose that the renewal of air to this cavity is accom- 
plished by the “ deglutition method,” and that, while this passage 
was open, the membrana tympani was in a relaxed or less concave 
condition than it was when either temporary or permanent recovery 
had taken place. 
The result of experiments contradicts the supposition that the 
pathological condition of this passage, aside from the patency— 
which affects the hearing only from a physical cause—had much in- 
fluence in producing these phenomena. That mere patency did have 
this effect has been frequently and clearly demonstrated ; and that this 
effect of the opening of the tube is not due to its pathological con- 
dition is just as clearly proven by the fact that the instant this pas- 
sage was closed by the abstraction of air from the cavitv before the 
inflammation of the mucous membrane that caused it had subsided, 
the whole train of symptoms at once disappeared, remaining away 
while the tube was closed. When the patients were successful in 
this abstraction of air and closure of the tube, they were also suc- 
cessful in banishing the entire phenomena of patency and most of 
the disability of their hearing. Their inability to keep this passage 
permanently closed was the only reason that compelled them to seek 
the assistance of the Aurist, otherwise they would not have com- 
plained of their hearing. 
It will be remembered that I stated that Mr. Toynbee was mis- 
taken about the condition of that portion of the eustachian tube, 
just beyond the attachment of the tensor palati, during the act of 
deglutition ; consequently in error in his deductions arrived at in his 
first experiment. 
It is generally considered that the act of deglutition, in immedi- 
ately removing the prominent symptoms, and the main disability to First Experime?it. 
27 
the hearing, occasioned by the inflation of the middle ear, by the 
Valsalvian method, is proof of the complete opening of the eusta- 
chian tube into the cavity, and the complete restoration of the usual 
degree of acuteness of hearing. This has been received by the Med- 
ical Profession, and passed by them, as far as known to me, unques- 
tioned, or rather, untested by any special or exact measurement 
during the experiment. 
It will be found, upon close observation, that the hearing is not as 
perfect for a short time, immediately after the prominent symptoms, 
occasioned by the inflation of the cavity, have been made to disap- 
pear by the act of deglutition, as it was previous to the inflation. 
The following method of making this experiment, with a normal ear, 
will prove the correctness of this assertion, viz.: 
First Experiment.—First, attach one end of a long thread to a 
watch, retaining the other extremity in the hand, then find the ut- 
most hearing distance from the watch (in the usual method of testing 
the hearing), placing the taut thread up to the nose; the length of 
this thread, from the nose to the watch, being the normal hearing 
distance from the watch. Second, now inflate the tympanic cavity 
by the Valsalvian method, then immediately perform the act of de- 
glutition, and instantly note the hearing distance from the watch on 
the thread. This will be found to be a little less than it was before 
the inflation, only returning again to the usual hearing distance after 
a short period of time.* 
*The following are the reports of a few of my friends, who tried this experiment 
at my request: 
“Feb. 9, 1868.—I heard the watch nearly twelve feet. I then blowed my 
breath in my ears, producing a great fulness. After I swallowed some saliva this 
left me entirely; but I had to step half a step nearer the watch to hear it, and in 
a few minutes, not more than two or three, I heard it again better than before. 
“James E.” 
“ July 29, 1872.—After repeated efforts, I overcame the desire to swallow a 
second time, and found that the usual hearing returned in from three to five min- 
utes after the first act of swallowing. If I swallowed two times, it returned sooner; 
even if I swallowed as often as I desired, I was still compelled to wait certainly 
over half a minute for the usual hearing to return. 
“J. C. W., Lebanon, 111.” 
“Aug. 6, 1872.—(Watch covered.) Inflated my ears, and immediately swal- 
lowed twice, and heard at second knot inches) natural, in 26 seconds 
[23 inches]. E. A. H., Collinsville, 111.” 28 
First Experiment. 
This shortening of the hearing distance demonstrates that the air 
did not all escape from the cavity during the act of deglutition, (rst 
and 2d Props.) If the eustachian tube was opened all the way into 
the middle ear, the air within and without the tympanum would have 
been instantly equalized, allowing the membrana tympani as instantly 
to resume its normal position for as perfect hearing as there was be- 
fore the inflation. Evidently there was a small portion of the 
eustachian tube that was not opened by the action of the tensor and 
levator palati muscles, and that the part or portion of the tube that 
was not opened offered so little resistance to the passage of the supera- 
bundant air contained in the cavity that the tensor-tympani muscle, 
assisted by the natural resilience of the membrana tympani, was able 
to force out a sufficient quantity of this air to relieve the ear of the 
prominent symptoms occasioned by its presence; still leaving too 
much in there for the usual hearing to return, compelling the exper- 
imenter to wait a short time for the mucous membrane of the cavity 
to absorb the remaining portion of the superabundant air (that the 
act of deglutition could not give opportunity to escape), which 
allowed the membrana tympani to become more flat than normal. 
After waiting for the consummation of this rarefying process the usual 
degree of hearing returned. 
I will now make a few quotations from recognized authorities, 
with the view of bringing prominently before the mind, that it is a 
requisite of normal hearing that there should be a uniformity of air 
density in the tympanic cavity; and by the same authorities, and ex- 
periments, and cited cases, I will show that there is a continual 
absorption (or, at least, a disappearance) of air within the cavity, and, 
consequently, a corresponding supply. (3d Prop.) 
The arguments based on these quotations—the result of these ex- 
periments, and the detailed statements of the cases cited, will show 
that there is a greater uniformity of air supply, according to the 
views here presented, than can be done by the “Toynbee method;” 
that is to say, that the means of furnishing air to the cavity must 
operate as continuously as the absorption, and that this “ deglutition 
method ” is not, and of necessity, in the nature of the case, can not, 
be as uniform in replenishing air to the cavity as its abstraction by 
absorption from the cavity. Toynbee's Theory. 
29 
In the quotations, I wish the following points to be kept promi- 
nently in view : first, the assumed necessity of uniformity of air den- 
sity in the cavity for normal hearing; second, the necessity for a 
method of supply to maintain this uniformity; therefore, the prob- 
lem presented by them for solution is this: how can these two im- 
perative necessities be maintained at the same time ? They affirming 
that this is done by the action of certain muscles, opening the 
eustachian tube all of the way into the cavity during the act of deglu- 
tition. 
Toynbee, on page 192, explaining his method of maintaining a 
uniform air density in the tympanum, says: “ During the few mo- 
ments that the faucial muscles are brought into play in the process 
of deglutition, air can either enter or recede from the tympanic cav- 
ity, and thus be always of the same density as the outer air.” On 
page 193 he gives his reasons why a constant supply of air is neces- 
sary, saying : “ Although from the preceding remarks there can re- 
main little doubt that the faucial orifice of the eustachian tube is 
ordinarily closed, except during the act of deglutition, it is requisite 
to perfect hearing that the tube should be pervious, and that there 
should be a constant interchange of air in the cavity of the tympanum. 
If the eustachian tube becomes impervious, the air that was in the 
tympanum at the time of the closure gradually disappears. It is 
not easy to decide whether it is absorbed, or whether by a kind of 
exosmose it passes through the membrana tympani; but whatever 
the cause, in a space of time varying in different cases from a few 
hours to a day or two, there is no doubt the air in the tympanic 
cavity becomes partially exhausted. The effect is to produce an 
increased concavity in the external surface of the membrana tym- 
pani ; a forcing inward of the chain of ossicles; pressure on the con- 
tents of the labyrinth; and a very serious diminution of the hearing 
power.” 
In the last edition of “Troltsch on the Ear,” page 180, the author 
says, speaking of the eustachian tube, “ It serves an outlet for the 
secretion of the latter (the cavity), but especially as a passage for the 
renewal of the air in the middle ear. It is, therefore, a ventilation 
tube, by means of which the meeting of strata of air of equal density 
before and behind the drum is made possible, and the air in the Troltsch's Theory. 
tympanum maintained of the same degree of tension as that of the 
external atmosphere.” 
Again, on page 187 : “ But if the tube is at the same time to be 
a ventilation tube, by means of which a regular exchange of air be- 
tween the pharynx and the cavity of the tympanum is brought about, 
it is necessary that its regular and frequent gaping or opening should 
take place only in this wise, that the strata of air before and behind 
the membrana tympani be kept of the same tension and density that 
is requisite for a normal vibratory capacity for the drum. Experi- 
ence has shown that such an opening of the tube takes place with 
every act of deglutition.” 
It will be seen that the chief purpose of the authors is to rationally 
account for the fact of a uniformity of air density in the tympanic 
cavity, and they aim to prove that this is accomplished during the 
act of deglutition. 
My effort will be to demonstrate that this mode of replenishing 
air to the tympanum is not so “ frequent ” as to admit of its being 
as “ regular ” as the abstraction of air from the cavity—that is to say, 
that the mucous membrane, in exhausting the air in the closed tym- 
panic cavity, is more uniform in its action than the act of deglutition, 
irregularly performed, can be in its supply to this cavity. 
It seems to me that it is superfluous to say, that there is no possi- 
bility of this cavity being uniformly supplied with air by an irregular 
act; yet, according to the quotations, the tympanum must await upon 
such an act. Keeping in mind the constancy and rapidity * of air 
absorption within the cavity, the longer the interval of time betyveen 
those acts that supply this air the greater must be the variation be- 
tween the internal and external air densities; therefore, good hear- 
ing must of necessity be of an intermittent character, synchronous 
with the act of deglutition. The following experiment will help to 
test whether this is the case or not. 
Second Experiment.—Let the experimenter place a watch (with a 
thread attached to it and employed for the same purpose as men- 
tioned in the First Experiment) as far from his ear as he can hear it, 
marking this place on the thread by a knot; remain in this position 
without performing the act of deglutition for a number of hours. It 
* See 4th Experiment, and Cases VI and VII. Second Experiment. 
31 
will be found that his hearing the tick of the watch at the end of two 
hours will be just as acute as at the beginning of the trial, and that 
he could hear the sound at any time he turned his attention to it 
during this experiment.* 
It is certain that in this condition of the eustachian tube there 
could not have been as uniform a supply of air to the tympanum as 
there must have been uniform absorption of air within the cavity, 
and yet the hearing is just as acute after this long non-performance 
of the only act that Toynbee, Troltsch and others allow for the 
renewal of air to the cavity, as before the experiment, when he swal- 
lowed as often as he desired. 
The result of this experiment seems to prove one of two facts— 
viz.: (a) That either there was no rarefaction of air within the 
tympanum by absorption, (b) or that the supply of air to the cavity 
must have permeated the eustachian tube as continuously as it was 
requisite to maintain the normal tympanic air density. (3d Prop.). 
Every case of that numerous class known as “ Obstructed Eusta- 
cian Tubes,” on account of chronic inflammation of the mucous 
membrane lining them, will bear the same evidence as this experi- 
ment and the first one—viz.: that at the act of deglutition this pas- 
* The following are the reports of a few of my friends who attempted this ex- 
periment, viz.: 
“ March ioth, 1868.—I commenced to listen to the tick of father’s watch at 3 
o’clock, but was compelled to swallow before the first three minutes passed, then 
I did not swallow for nearly twelve minutes, then I swallowed in five minutes, the 
next time I did not swallow for nearly one hour, but my throat [by this time] was 
very dry. I heard the watch one time as well as the other. Jennie E. D.” 
“ March ioth, 1872.—Commenced to listen to the watch (covered) at 2 o’clock 
P. M., and swallowed only when I was compelled to, at 2.03, 2.06, 2.26, 3.03, 
3.16, 4.08, 4.44, and 5.37. I heard the watch equally well all the time, 
but my throat was a little sore when I got done. Bella R.” 
“ March 21st, 1872.—I made the same experiment, and swallowed at 1, 1.08, 
1.46, 2.20, 4.13, 5.12, 6.27. Distance just 6 feet. I heard the watch this time 
also as well at one time as another. Bella R.” 
“April 8th, 1872.—Commenced to listen at 9 A. M., and did not swallow, be- 
cause my throat was very sore [occasioned by tonsilitis], until 11.30 A. M., and 
then only because I forgot. Commenced again at 1.30 p. M., and did not swal- 
low for just three hours. My hearing was not very good when I started, but was 
equally good at any time I listened to the tick of the watch. H. Lee J.” 32 
Air Permeation to the Cavity. 
sage is not opened into the tympanum, yet the amount of their hear- 
ing proves that the air slowly and continuously permeates through 
the abnormally closed tubes into the middle ear, although not suffi- 
ciently rapid for good hearing. That there is air permeation in this 
condition of the tube in all such cases of this class is evident, because 
of the degree of hearing being much greater, and the concavity of 
the membrana tympani much less, than in cases having acute tubal 
catarrh, where little or no air can enter, because of excess of secre- 
tion. If the air does not enter the cavity at all, then the deafness 
would be as great as in any case of complete closure of the tube, and 
the concavity of the membrana tympani would also be as great, for 
the length of time giving opportunity for air absorption is certainly 
long enough to accomplish this. It is also just as evident that the air 
does not enter the tympanic cavity during deglutition, for if this act 
opened the tube, what would hinder the hearing from being instantly 
increased, as it is by the inflation of the cavity by the Politzer air 
douche ? That the hearing is increased by this inflation, I take it, 
is strong evidence that the eustachian tube was not opened into the 
cavity at the act of deglutition. It may be claimed that the action 
of the tensor and levator palati muscles in those cases do at least 
give some opportunity for air to enter the cavity, but not sufficient 
on account of the thickening of the mucous membrane of the tube. 
Then relief for all such cases is constantly at hand; is it not evident 
that the prescription to perform frequent acts of deglutition would 
be the remedy, thus allowing more air to enter the cavity; making 
the Politzer air douche needless; and that the continued exercise of 
this faculty would increase the hearing, until the one-sided pressure 
on the membrana tympani was neutralized, and its normal position 
attained ? 
The following experiment will not only corroborate the views here 
expressed concerning air permeation through the normally closed 
eustachian tube, but will show more demonstratively than any ex- 
periment yet given that air can enter the tympanum without the aid 
of the act of deglutition, even more rapidly than is required; show- 
ing that there is no necessity for any action of the tensor and levator 
palati muscles to open this passage to the middle ear for the normal 
renewal of air to this cavity. Third Experiment.—Proving Air Permeation. 
33 
Third Experiment.—First find the utmost distance from the watch 
with the aid of the thread, as before stated; note this. Second, close 
the nostrils with the thumb and forefinger, and perform the act of 
deglutition several times, thus abstracting the air from the middle 
ear, so as to decrease the hearing as much as possible; immediately 
after this again find the hearing distance from the watch, and note 
this on the thread; continue every five minutes to make these ob- 
servations of the hearing distance for a period of half an hour, all 
this time refraining from performing the act of deglutition. It will 
be found that the hearing distance from the watch will continously 
increase, although there has been no act to open the eustachian tube 
to assist in replenishing the cavity with air.* 
Evidently the cause of this increase of hearing distance from the 
watch, under these circumstances, is due to the tympanum being 
again replenished with air, so as to allow the membrana tympani to 
return to its normal position. But from what direction did this air 
come ?—by what avenue ? I take it that this is as conclusive evi- 
dence as could be required to prove air permeation through the 
normally closed eustachian tube into the cavity. 
Although the celerity of the air exhaustion within the cavity is 
not in dispute, it is nevertheless evident that great importance must 
be attached to the rapidity of this disappearance, when the question 
* “Collinsville, III., April 24th, 1872.—Found the normal hearing [watch 
covered] at length of this (shorter) string [487/] at 9 A. M; swallowed with nose 
closed and heard at first loop at 9.04 at original distance. Swallow and 
heard at same. [Repeated several times.] * E. A. H.” 
“St. Louis, April 24th, 1872.—First found distance [64^"] that I heard the 
watch, then I cut the cord, closed my nose and swallowed 
At 12.45 p- M>> and heard at 1st knot [48)^//.] 
At 12.50 “ “ “ 2d “ [60 
At 12.52 “ “ “ full length [64^''.j 
Second trial.—At 8 35 P. M., heard at 1st knot [49yk"-~\ 
At 8.40 “ “ 2d “ [54^^.] 
At 8.45 “ “ 3d “ [6i#".] 
At 8.50 “ “ 4th “ [62^".] 
At 8.55 “ “ 5th “ [67".] 
At 8.57 “ same as at the start 
Amelia F. 
(Teacher in one of the Public Schools.) 34 
Fourth Experiment.—Proving Rapid Air Absorption. 
of air supply to the tympanum is under consideration, as slow ab- 
straction only requires slow renewal, but rapid abstraction an equally 
rapid supply. For the purpose of placing this important function of 
the mucous membrane prominently before the mind, so that due 
importance may be attributed to the method of supplying the deple- 
tion thus continually going on, the following experiment is given, 
viz.: 
Fourth Experiment.—First find the utmost hearing distance from 
the watch, aided by the thread in measuring as before mentioned; 
note this. Second, inflate the middle ear by the Valsalvian method, 
thus forcing, by superabundant air, the membrana tympani away 
from its normal position, dragging with it the ossicula auditus; Im- 
mediately after this inflation again note on the thread the hearing 
distance. Continue making these observations every five minutes 
for half an hour, refraining from performing the act of deglutition 
during the experiment. With those experimenters whose eustachian 
tubes are normal, this inflation will decrease the hearing; and with 
those having an inflamed mucous membrane of this organ, lessening 
the opportunity for air to enter the middle ear, it will increase the 
hearing; and with those whose tubes allow an excess of air—bor- 
dering on patency—it will decrease the hearing; but with either 
party it will be found that the usual amount of hearing will soon 
return. As this usual hearing could not return until the membrana 
tympani and ossicula auditus also returned to their usual position, 
it is, therefore, conclusive evidence that the superabundant air was 
abstracted by some means, and as the act of deglutition was not 
performed, it must have been rapidly taken away by the action of 
the mucous membrane of the cavity. 
From the result of this experiment it is evident that air abstrac- 
tion from the tympanum is not a very slow process. 
We have other means of measuring the rapidity of the air absorp- 
tion in this cavity. For this purpose I will relate, as briefly as is 
consistent with the importance of this subject, the observations made 
on the following cases of closed eustachian tubes by acute tubal 
catarrh, viz.: 
Case VI.—Master Freddie H., aged about nine years. Exam- 
ined first on July 25th, 1866. Has suffered for about three weeks Case VI.—Proving Rapid Air Absorption. 
35 
from a very severe cold in the head; his throat was also much 
affected; tonsils enlarged: breathed entirely through the mouth. 
Supposed cause, prolonged bathing. Hears the watch in both ears 
only on slight pressure; has considerable pain in the ears, and under 
them toward the throat. The membrana tympani of both ears were 
very concave. 
Attempted to inflate the tympanic cavities by the Politzer air 
douche, but failed; also failed on the 26th, but on the 28th was suc- 
cessful in opening the left tube, increasing the hearing in this ear to 
12" (normal hearing distance of the watch about 120"). 
Aug. 3A—Hearing to-day same as before treatment; was again 
unsuccessful in inflating either cavity. 
Aug. \th.—His mother accompanied him to-day, stating that his 
improved hearing of last Saturday did not last until he got home. 
Was again unsuccessful in inflating the tympanic cavities. 
Aug. 6th.—To-day opened both tubes by the air douche. The 
hearing was not examined before the treatment, but this inflation 
increased this in the right ear to 13", in left to 15". 
' Aug. 7th.—Watch heard with both ears only when nearly in con- 
tact. One successful air douche increased the hearing in right to 
9y/, left to 11". Three other douches to 14" on right side, and 1714" 
on left. 
Aug. qth.—Hearing in right in left 4". After inflation of 
middle ears by seven air douches his hearing was increased to i8yyin 
right, and 2 2yy in left. This was about 10.30 a. m. He did not leave 
the office until 12 m., when, on examination, his hearing with right 
ear was 7yy, left 10". Here was a loss in one and a half hours on 
the right side of 11yy on the left 12 n. Three more douches increased 
the hearing to 2ii^/yand 2 7yy, respectively. 
Aug. 10th.—To-day there was a loss in two hours of i3/yin right, 
and i8y/in left. 
Aug. 11 th.—Loss to day in one and a half hours 7y/in right, and 
i3^/yin left. 
About the same amount of loss of hearing followed the next four 
treatments; this was also noticed by the father of the patient. The 
observation of this decrease of the hearing so soon after the treat- 
ment was first made by the mother of the patient (who was a teacher 36 
Case VII.—Rapid Decrease of Hearing. 
in one of our public schools); and it was her remarks about it, that 
were the cause of its being noted by me. 
Case VII.—The next case in which I took notice of the amount 
of hearing lost after treatment, was my niece, Miss Lizzie I. R., aged 
ten years. Her tonsils were very much enlarged. Hearing watch 
with right ear contact, left i77 The first inflation caused a very loud 
crack in her ears, frightening her very much. After this air douche 
she heard the watch with the right ear i8/7, left 32/y. I tried for 
about half of an hour to persuade her to allow me to make another 
application of the douche, but in vain. Her hearing at this time 
was reduced u^77on right side, and left, a loss during this 
half hour of 6^y/in right, and i37/in left. Four days afterward— 
March 9th, 1867—her hearing on right side was contact, left i^7'; 
after one air douche, right ear 1777 left 3577; after another, right 2277, 
left 46then was compelled, on account of the very great dread of 
the effect or noise that the inflation caused, to desist until 2 p. m., 
when her father came to my assistance. After she had been away 
nearly four hours, her hearing had decreased to i2//on right side, 
and 27" on left, a loss in this time of io77on right, and 19'7on left. 
The history of quite a number of similar cases could be added, 
demonstrating the rapidity of the absorption or disappearance of air 
within the cavity of the tympanum.* 
If the “ deglutition method ” of renewing air to the tympanum is 
correct, the experimenter that refrained from performing the act of 
deglutition for two hours, must have been as deaf as either of those 
cases having tubal catarrh, two hours after their treatment, for 
neither, according to the Toynbee theory, had any means or oppor- 
tunity of supplying air to the middle ear, in the place of that ab- 
stracted by the mucous membrane of the cavity, and this should 
have caused an equal loss of equilibrium in the tympanic air density 
in both individuals, consequently an equal loss of hearing; but the 
results prove that those having normal eustachian tubes did not suf- 
fer in this respect, by reason of this long so-called closure (3d Prop.); 
whereas, those cases having abnormally closed eustachian tubes, did 
* I have observed the hearing decreased by this means at the rate of from 
it," in two hours to 16" in five minutes. Necessity For Continuous Air Supply. 
37 
seriously suffer loss of their hearing, even after a much shorter period 
of closure. 
The Fourth Experiment, and the facts observed of the VI and 
VII Cases, abundantly prove that even if the act that is claimed to 
open the eustachian tube was performed every minute during life, it 
would not be sufficiently “ frequent ” to maintain the requisite uni- 
formity of air density in the cavity to admit of perfectly uniform 
hearing. A continuous air absorption necessitates a continuous re- 
newal. Either you must stop the continuous abstraction, or you 
must allow the continuous supply. The alternative is physically 
unavoidable. 
Again, I deem it self-evident that a uniform tympanic air density 
implies that there must be a uniform condition of the eustachian tube; 
therefore, this passage must be uniformly open, or uniformly closed. 
It is impossible that it can be closed a large majority of the time, 
and open at accidental intervals, and there exist at the same time 
a uniform air density in the tympanic cavity while air absorption is 
continuous. Now, if the walls of the eustachian tube are constantly 
in contact, or only in contact during the interval between the acts 
of deglutition, in what condition will the air that remains in the 
cavity be in respect to its density, as compared with that on the 
outside ? Most certainly it will soon be in a rarefied condition (4th 
Prop.), unless it can as freely and continually enter the cavity as if 
it had a patent tube to admit it. Even if the “ deglutition method ” 
of tympanic ventilation is correct, much the greater period of time, 
this air in the cavity must be in a rarefied condition, as the absorp- 
tion is rapid enough to produce this effect upon it, and the act of 
deglutition is not “ frequent ” enough in its supply to prevent it. 
From this it appears as though there would be a necessity for a 
patency of the eustachian tube;—that is, if the normal air density in 
the middle ear must—as asserted by Toynbee, Troltsch, and oth- 
ers—be maintained equal to that of the surrounding atmosphere; 
but instead of this, there is, in my opinion, a physical necessity for a 
rarefied condition of the air density in the middle ear, even if the 
eustachian tube was only closed for a short period of time, to allow 
the oscillations of the membrana tympani to move with greater free- 
dom and sweep, and prevent undue condensation of air in the tym- 38 
Resume.—First Proposition. 
panum from the vibrations of the membrane occasioned by the waves 
of sound. 
RESUME. 
The First Proposition—“ That during the act of deglutition the 
eustachian tube is not an open passage into the tympanum ”—has 
been sustained by the fact that the increased concavity of the mem- 
bran® tympani of those patients that recover from the disability of 
their hearing occasioned by the patency of their eustachian tubes, 
as compared with its curvature before their recovery. We have 
seen that after their hearing has been permanently increased the 
act of deglutition does not cause their membranae tympani to become 
less concave as it did before their recovery. Now, as we know, that 
they increased the concavity of their membrane by abstracting air 
from the middle ear, and as the closure of the tube was necessary to 
maintain this concavity, it is evident that if the act of deglutition 
opened the tube, this maintained curvature would be instantly 
released, allowing the membrane to become less concave, conse- 
quently give rise to the well-marked phenomena of patency, as it 
did in Mr Toynbee’s first case, and my second.* 
The First Experiment (also Mr. Toynbee’s first, page 190,) de- 
monstrate that the eustachian tube is not completely opened during 
the act of deglutition, but only so much of it as to make it possible 
for the natural resiliency of the membrana tympani, assisted by the 
traction of the tensor tympani, to force out sufficient of the super- 
abundant air that occasioned the prominent symptoms that follow 
filling the middle by the Valsalvian method, still leaving too much 
air in the cavity for the usual hearing to return, as proved by exact 
measurement, aided by a thread, compelling the experimenter to wait 
a short time for the mucous membrane of the tympanum to exhaust 
the remaining excess of air—that did not have opportunity to escape 
during the act of deglutition—that permitted the membrane to as- 
sume a less concave condition than normal. After the consumma- 
tion of this rarefying process the usual degree of hearing returned. 
Every case, whose hearing is limited on account of chronic inflam- 
mation of the mucous membrane of the eustachian tube, will bear 
the same evidence. If the act of deglutition opened their eustachian 
tubes, why does it not increase their hearing as instantly as does the 
Politzer air douche ? That they require this inflation to increase 
their hearing, is the strongest proof that air did not enter the tym- 
panic cavity during the action of the tensor and levator palati mus- 
cles. It cannot be admitted that the action of these muscles allow 
any air to enter the middle ear; if this was the case, then frequent 
acts of deglutition would make the air douche needless, and that the 
continued exercise of this faculty would increase the hearing, until 
the one-sided pressure on the membrana tympani was neutralized, 
* See pages io and 19, Resume.—Second and Third Propositions. 
39 
and its normal position attained. Nor would it be correct to assert 
that their middle ears did not receive any air, as this would cause 
them to be as deaf as cases afflicted with acute tubal catarrh. 
The Second Proposition—“ That the walls of the eustachian tube 
are constantly in slight contact ”—is substantiated by the uniform 
constancy of the concavity of the membrange tympani of those cases 
of patency of the eustachian tube after their recovery. It is evident 
that the increased concavity of their membranse tympani was con- 
comitant with their increased hearing, and that the increased curva- 
ture was caused solely by air abstraction, and this rarefaction could 
not in this way affect the membrane with an open tube. The con- 
tinuance of the increased concavity proves a constantly closed eusta- 
chian passage. 
The failure of the return of the usual degree of acuteness of hear- 
ing, after the act of deglutition relieved the symptoms occasioned 
by inflation of the middle ear, as shown by First Experiment, also 
proves that the entire length of the eustachian tube was not opened 
by the action of the tensor and levator palati muscles. 
The Third Proposition—“ That the air continously permeates the 
eustachian tube into the tympanum, thus maintaining the normal air 
density ”—is proved by the continuance of uniform hearing in every 
normal ear. It is well known that there is absorption of air in the 
tympanum which must be removed; therefore, if this supply is uni- 
formly added, the concavity of the membrana tympani is also neces- 
sarily uniform; but, if infrequent and irregular, the shock of its 
entrance would suddenly affect the membrana tympani, consequently 
the hearing. Therefore, this mode of renewing air to the middle 
ear would give rise to an irregular hearing, which is not in accord- 
ance with our observations. 
That the air does permeate the eustachian tube, is shown by the 
Second Experiment—that of refraining from performing the act of 
deglutition for two hours without affecting the acuteness of hearing 
in the least degree. Whence did this experimenter receive a uniform 
supply of air to maintain this uniform hearing ? If we will com- 
pare this result with the facts observed in VI and VII Cases, that 
had abnormally closed eustachian tubes, because of acute tubal 
catarrh, whose loss of hearing one and a half hours after inflation of 
middle ears were 12" and 13" respectively, we will find in the con- 
trast another evidence of the truth of this Proposition. It is appar- 
ent that the eustachian tubes of the experimenter—in the Second 
Experiment—and those of the patients just mentioned, were what is 
usually understood as closed, consequently they were equally cir- 
cumstanced as to their opportunity for renewing the air in their mid- 
dle ears; but the results prove that the experimenter, having nor- 
mal tubes, did not have his hearing affected in the least by this long 
so-called closure, but those having abnormally closed tubes were 
seriously affected in their hearing after a shorter lapse of time. 
That the air can permeate the eustachian tube even faster than is 40 
Resume.—Fourth, Fifth and Sixth Propositions. 
necessary for the normal ventilation of the tympanum, is proved by 
the Third Experiment—namely, that of abstracting air from the mid- 
dle ear by performing the act of deglutition while the nostrils are 
closed, then refraining from swallowing during the experiment, thus 
decreasing the hearing. It will be found that the hearing will return 
to its usual degree of acuteness in a few moments. There can be 
no doubt but that the cause of this increase of hearing, under these 
circumstances, is due to the tympanic cavity being again replenished 
with the normal amount of air, even more rapidly than is requisite 
for the normal supply to this cavity. 
The Fourth Proposition—“That the air in the normal tympanic 
cavity is not of equal density with that on the outside, the air in the 
tympanum being rarefied ”—is proved by the observation that there 
is increased concavity of the membranse tympani of those cases of 
patency of the eustachian passage that improve in their hearing. 
We have seen that this increase of curvature did not take place 
when the air densities on both sides of the membrane were equal, 
and that the act that the patients performed for the relief of their 
disability of hearing abstracted air from the cavity, causing the mem- 
brane to recede inward, thereby increasing their hearing. The co- 
existence of these facts affirm that the air in the normal middle ear 
is in a rarefied condition. 
The Fifth Proposition—‘i That one of the functions of the eusta- 
chian tube is the maintenance of this normal air density ”—is sus- 
tained by the evidence of the necessity of an increased concavity of 
the membrana tympani, in cases suffering from abnormally open 
eustachian tubes, for increased hearing. It is evident that the 
rarefaction of air in the middle ear that sustains this concavity, 
must be maintained by a graduated and uniform entrance of the 
supply into the tympanum. 
The Sixth Proposition—“ That the rarefied condition of the air 
in the tympanum is the cause of the uniform concavity of the mem- 
brana tympani, especially that portion from which the ‘ light spot ’ 
is reflected ”—is substantiated by the observation made by the meth- 
ods that patients afflicted with abnormally open eustachian tubes 
take to reduce their flat membranae tympani to a more concave con- 
dition—i. e., making an inspiratory effort, or performing the act of 
deglutition with their nostrils closed. There are no facts showing 
that the combined action of the circular and radiating muscular 
fibres in this organ maintain its normal concavity. We have seen 
that patients who have abnormally flat membrante tympani improve 
their hearing by a voluntary act (rarefying the air in the middle ear) 
that cannot restore any muscular inability that might be said to affect 
it. It has frequently been observed by Aurists that a cicatricial por- 
tion of a membrana tympani is always concave. It is certain that 
this formation has no circular or radiating muscular fibres; its uni- 
form concavity cannot be said to be maintained by such means.