HOW A LESION OF THE BRAIN RESULTS IN 
THAT DISTURBANCE OF CONSCIOUSNESS 
KNOWN AS SENSORY APHASIA 
HY 
MORTON PRINCE, M.D. 
PHYSICIAN FOR NERVOUS DISEASES, OUT-PATIENT DEPARTMENT, BOSTON CITY HOSPITAL ; 
PHYSICIAN FOR NERVOUS DISEASES, BOSTON DISPENSARY 
[Reprinted from the Journal of Nervous and Mental Disease, Vol. xii., 
No. 3, July, 1885.] HOW A LESION OF THE BRAIN RESULTS IN 
THAT DISTURBANCE OF CONSCIOUSNESS 
KNOWN AS SENSORY APHASIA.1 
By MORTON PRINCE, M.D., 
PHYSICIAN FOR NERVOUS DISEASES, OUT-PATIENT DEPARTMENT, BOSTON CITY HOSPITAL. 
PHYSICIAN FOR NERVOUS DISEASES, BOSTON DISPENSARY. 
WHEN Broca demonstrated that an injury to the 
base of the third frontal convolution on the left 
side of the brain caused a loss of the power of speech, the 
first step was taken towards the exact localization of the 
functions of the brain. But though all subsequent experi- 
ence has confirmed Broca’s discovery, more recent clinical 
observation has shown that this region is not the only one 
the integrity of which is essential for the function of lan- 
guage ; but that the destruction of other regions, as, for 
example, the Island of Reil, the first two temporal and 
other convolutions, result in the impairment of this faculty. 
But, on the other hand, while it has been shown that this is 
the case, it has also been determined that there are differ- 
ences in the symptoms presented according as the impair- 
ment of speech is due to an injury to Broca’s convolution, 
or to some other spot. In other words, all aphasia is not 
the same, but that the faculties retained and lost by 
1 Read at the annual meeting of the Massachusetts Medical Society, June 9, 
1885. 
Reprinted from the Journal of Nervous and Mental Disease, Vol. xii., 
No, 3, July, 1885. 2 
MORTON PRINCR. 
aphasics differ; some for example can perfectly understand 
when spoken to, but cannot articulate or write; others can 
articulate, but cannot understand a single spoken word 
though they hear perfectly all other sounds; others can 
both understand spoken language and speak, but their 
speech is unintelligible; and so on. Various attempts 
accordingly have been made to construct a number of 
different types of aphasia, to which all cases may be more 
or less approximated. To understand the phenomena of 
aphasia it is necessary to carefully study the faculty of 
language as possessed by a normal individual. I have no 
intention of doing so here, further than to point out that 
for the complete faculty of speech, which is a complex func- 
tion, the co-operation of at least three different functions is 
requisite. In the first place, it is necessary to be able to 
hear the sounds of words, internally as well as externally ; 
for a person may be deaf to words, though he has most 
acute hearing for all other sounds. Secondly, there must be 
a sufficiently normal intellect, in order that words may be 
combined with ideas ; and thirdly, we must be able to co-ordi- 
nate the motor impulses to the muscles of the apparatus of 
speech. Clinical observation has further shown that these 
different faculties are distinct and separate, and that one 
can be lost while the other two are retained; but that the 
impairment of any one, whether of the acoustic, the motor, 
or the intellectual faculties, results in an impairment of 
speech, or aphasia. We are thus compelled to distinguish 
different centres in the brain corresponding to each of these 
functions—namely: an acoustic centre where the sounds of 
words alone arise; a motor centre, where the impulses to 
the muscles of speech are co-ordinated; and a larger and 
diffuse centre for the intellect proper, where the word-sounds 
are associated with ideas. As the impairment of the intel- 
lectual centres comes within the domain of insanity it need 
not concern us further here. When the motor centre is 
affected, the resulting disturbance of speech is known as 
motor, ataxic or Broca's aphasia; when the acoustic centre 
is at fault, as sensory or sometimes paraphasia. These are 
two of the principal forms of aphasia. Other forms have SENSORY APHASIA. 
3 
been distinguished, but it is not necessary for my purpose 
to consider them here. 
Motor aphasia is the most common form. I will not tres- 
pass on your time by narrating cases of this well known 
type, but will briefly mention the following case, in order 
that the type may be contrasted with the second variety. 
A young woman, Hannah D., had an attack of apoplexy two 
years and five months before I saw her, and following an attack 
of rheumatism and probably endo-carditis. At the time of my 
examination the right hemiplegia, which at first had existed, had 
entirely disappeared. Aphasia only remained. The only im- 
provement of speech since the attack consists in the ability to say 
“No.” She cannot say “ Yes.” She can understand perfectly 
when spoken to. She can write her name but nothing more. She 
can read to herself, but not aloud. She cannot repeat spoken 
language. 
In this case there was : 
lost : 
a. Volitional speech, 
b. Repetition of words, 
c. Reading aloud. 
d. Volitional writing, 
e. Writing to dictation. 
RETAINED : 
/. Understanding of spoken 
language, 
g. Understanding of written 
language. 
(She could write to dictation “ Boston ” as far as “ Bo,” but not 
Massachusetts or any thing more.) 
Various schemes have been constructed to diagram- 
matically represent the mechanism of the different forms 
of aphasia. I may say here that, in my judgment, none of 
the many thus far constructed correctly accord with all 
the phenomena of aphasia, though the one given by Lich- 
theim is probably in the main correct. I have drawn on 
the board so much of it as is necessary for the purposes of 
this paper. This is probably correct so far as it goes. The 
intention is merely to schematically represent the different 
centres concerned in speech and their connection, without 
reference to what portion of the brain they are located in. 
a. is the auditory nerve which carries acoustic impressions 
to the centre A., where the word-sounds arise. B. is the 
centre for the intellect proper. M. the motor centre, and m. 
the motor nerves. A. B., B. M., and M. A. are commisural 
fibres connecting these centres. 4 
MORTON PRINCE. 
Fig. r. 
From a study of this scheme, if correct, it is apparent 
that seven different types of aphasia can theoretically occur, 
according as there is an injury to the centres A., B., M., or 
their connections. 
Lichtheim claims to be actually able to distinguish 
clinically these seven types. Be that as it may, the scheme 
enables us to understand the mechanism of the commonly 
recognized forms. In the motor form, of which I have 
just spoken, the centre M., where the motor impulses to the 
muscles are co-ordinated, is destroyed. Hence ideas in B. 
cannot resolve themselves into words. On the other hand 
we can understand how such a patient can readily under- 
stand when spoken to, as the auditory centre A., the intel- 
lect B., and the connection A. B. is intact. He might be 
able also to think in words, to write (?) and read (for sim- 
plicity’s sake I have not represented the centres for the 
latter two faculties), though he could not repeat words 
dictated. If the centre A. alone is destroyed we have the 
second form of aphasia I spoke of, namely, sensory aphasia. 
In such a case, though the patient can hear all other kinds 
of sounds, he is absolutely deaf to words. As B. and M. 
are intact the faculty of volitional speech is retained, but it 
is so modified that the patient uses the wrong words, and 
puts together syllables belonging to different words in such SENSORY APHASIA. 
5 
a way as often to make his sentences unintelligible. He 
has what is called paraphasia. He can properly co-ordinate 
the motor impulses so as to pronounce all the sounds of a 
language, but words and syllables are combined in an unin- 
telligent manner, owing to the defect in the word-conscious- 
ness at A. 
The following case of sensory aphasia has been recorded 
by Wernicke : 
The patient was an old woman who was thought to be insane, 
and accordingly sent to the insane asylum. There it was found 
that she was perfectly sane, but, though her hearing was acute for 
sounds, as tested by a watch, she was stone deaf for words—that is, 
she understood absolutely nothing that was said to her. Although 
she could speak (thereby differing from the motor aphasic), her 
language was often meaningless, from the fact that she inserted 
wrong words in her sentences, and often distorted and senseless 
words. The meaning of her language, however, could be un- 
ravelled, and was found to be rational. 
It is this form of aphasia, where the consciousness of the 
sound of the word is lost—sensory aphasia—which I propose 
to more fully consider here to-day. That there is a centre 
in the brain where the sound of the word is generated there 
can be no doubt. The case which I have just narrated to 
you conclusively shows this. This centre is distinct from 
that one where the the motor impulses, which control the 
articulation of words, originate, and the destruction of which 
results in ataxic or motor aphasia. In the diagram these 
centres have simply been indicated with their connections, 
without attempt to define their actual locations in the brain 
itself. In regard to their actual locations we are not yet 
prepared, perhaps, to express an opinion for all the centres. 
The motor centre without doubt is situated in the posterior 
third of the third frontal convolution, known as Broca’s 
convolution, and its neighborhood, in the region marked A. 
(Fig. 2). Pathology has clearly demonstrated this. The 
auditory centre, on the other hand, is less firmly established, 
though there is reason to believe that it is in the neighbor- 
hood of the Sylvian fissure in the first temporal convolution. 
Another case given by Wernicke points to this fact. It 
was that of a woman who was supposed to be crazy and 6 
MORTON PRINCE. 
deaf, but was found to be also suffering fiom word deafness 
and paraphasia. At the autopsy there was found a throm- 
bolic softening of the first and of a great part of the second 
left temporal convolution (Fig. 2, shaded portion). 
Fig. 2. (After Ferrier.) 
Now, the question which I am coming to is this : What 
do we mean by a centre for speech ? How does it happen 
that a destruction of this centre causes a loss of the power 
of speech, and in particular a loss of the power of hearing 
words ? In answer, you say that here in this temporal con- 
volution is the spot where the word-sounds are generated, 
and when this spot is destroyed, the apparatus is destroyed 
which generates the word-sounds. This is what is implied 
or hinted at in much of the language of medical text-books 
and periodical literature. If you will pause for a moment 
to reflect you will perceive that such language means either 
very little, or something which is so carelessly expressed as 
to border on nonsense. Can you conceive of the brain 
generating a sound as a gas machine generates gas? If you 
can, what manner of thing is the sound, and what becomes 
of it after it is generated ? Any notion of word-sounds, or 
any other form of conciousness being a product of the brain, 
is too crude to bear analysis. The moment you try to 
picture the process to your mind you are lost in a sea of 
contradictions. 
If one is more exact in the use of language, he says that 
the acoustic centre for words is the spot where the activity SEN SOU Y APHASIA. 
7 
of the brain is accompanied by the auditory sensations 
of words, and the destruction of which centre results in 
the loss of the faculty of understanding language, or think- 
ing in words internally. But again it may be asked: How 
does the destruction of the brain end in loss of word- 
sounds ? and why should the sounds be gone simply be- 
cause the brain is injured ? You have broken up a circum- 
scribed piece of the brain ; but do you see any likeness 
between that piece of brain and the sound of a word ? The 
sound is a form of our consciousness ; why then should it 
not exist though the brain be broken ? You may answer 
that it is the function of this part of the brain to Do 
what ?—produce word-sounds ? This brings us back to the 
difficulty of conceiving of a sound as something produced. 
Can you not conceive of your having sounds without a 
whole brain ? Why, then, I repeat, should the consciousness 
of words be gone because a spot of brain is broken up ? 
Examine this piece of brain as much as you please. Bring 
your microscopes to bear; dissect it till you have made 
out that it is made up of cells and nerve-fibres, of connec- 
tive tissue and blood-vessels ; analyze it in your chemical 
laboratory till you discover it is composed of protoplasm, 
of myelin, of fibrin, and what not. Increase the power 
of your lenses till you see the very molecules of protoplasm 
as they beat against one another in the myriads of cells of 
the brain, and after you have done all this, have you found 
any where any thing like a sound ? 
But sound is the function, you answer, of the brain. Well, 
look again through your microscope. Watch the blood 
course through the vessels ; watch it transude through the 
walls of these vessels into the cells; watch it transude back 
again after its chemical constitution has been metamor- 
phosed. Look into the cells themselves, and watch the very 
molecules as they vibrate in unison ; watch them, as the 
vibrating wave passes along the ingoing nerves into the 
cells, and watch how the wave passes out again as the mole- 
cules in the outgoing nerves take up the motion. Watch 
again the molecules as they combine and recombine in new 
proportions with the new food brought by the blood, and 8 
MORTON PRINCE. 
see others cast out as effete products of metamorphosis. 
You have now seen the function; have you come across 
any thing like the sound of a word ? Where then does 
this sound come in ? It is this question which I have 
brought before you for your consideration to-day, and 
which I shall endeavor to answer. 
Let us look a little more closely into what happens when 
an artery, for example, breaks in the brain. The cortex of 
the brain, as you know, is made up of cells and fibres. As 
a result of the rupture, the cells are disintegrated and the 
fibres severed. Along the latter neural currents are no 
longer carried, and in the cells nervous “ force,” so-called, 
is no longer generated,—the molecular vibrations which 
accompany a state of consciousness, as the sound of a word, 
can no longer occur. 
If we had examined more minutely the cells before they 
were broken up, we should have found that they are princi- 
pally made up of nervous protoplasm, a very complex sub- 
stance. We know that it is made up, like all material 
substances, of molecules, the smallest particles into which a 
substance can be divided without changing its composition. 
The activity of a nervous cell consists in the vibration of its 
compositeTnolecules. It is this activity which accompanies 
the word-sound. 
But still in viewing this activity, we have not yet got any 
nearer to the word-sound we are in search of. Let us go a 
step farther and examine what we mean by a molecule, and 
by molecular vibrations. A molecule is something which 
we picture to ourselves as having a certain shape and size ; 
if, in imagination, we press it between our fingers, we per- 
ceive it has a certain density and hardness ; we must regard 
it also as having a certain color similar to that of a large mass 
of the same substance. Furthermore, when acting in con- 
junction with other molecules we know it has a variety of 
physical and chemical properties. Its properties, as a whole, 
may be described as the resultant of the properties of its 
constituent atoms. 
But when we say that a molecule of protoplasm is of a 
certain color, shape, and size, etc., etc., what do we mean SENSORY APHASIA. 
9 
by this ? When we say that the molecules of protoplasm 
vibrate with one another what manner of thing is this 
vibration ? There is more in this question than seems at 
first sight. To answer it we must turn to our physiology, 
and inquire how it is that we see objects, and how it is that 
we recognize a molecule to have color, for example. What 
we shall find to be true of seeing, will also be found to be 
true of all our other senses. 
I am going to represent here on this blackboard by this 
star-shaped figure (Fig. 3, a) a molecule of protoplasm, 
which we will suppose is in a cell in the brain A. 
Fig. 3. 
We will imagine a person, B, inspecting it through the mi- 
croscope, C. The observer makes out that there is something 
there that is octagonal in outline, and blue in color. What is 
the physiological process by which he sees all this? Physics 
and physiology answer thus : The vibrating waves of the 
ether, c', c', coming from the sun are reflected, c, c, c, 
through the microscope, C, toward the eye, of the ob- 
server, B. After passing through the cornea, lens and 
vitreous humor of the eye they impinge upon the retina, d. 
If we pause a moment to consider what has occurred we 
may be surprised to find that nothing like color, or shape— 
indeed, nothing like a picture of a blue octagonal molecule, 
thus far exists. So far the only phenomena presented are 
oscillations of the molecules of ether between a point, a, 
and the retina ; but now the motions of the etherial mole- 
cules are transmitted to the retina, and to the molecules of 10 
MORTON PRINCE. 
the nervous protoplasm in the optic nerve. Along the 
optic nerve, along its prolongations, deep into the brain, the 
motion is continued, till the waves reach the occipital fobe 
of the brain; here the cells of the cortex are at last reached, 
and to the molecules in these cells the motion is com- 
municated. Even then, till we reach these cells, nothing 
like color has appeared. Sever the lines of communication 
at any point between a and the cells of the cortex and 
nothing like color exists, though the molecules of ether 
around a are still in agitation. But at last the motion has 
been transmitted to the cells in the cortex of the brain, 
and now, for the first time, color arises, and the sensation of 
blueness, b, is excited. The observer looking through the 
microscope is conscious of blueness ; but now an artificial 
device comes into play, and the observer says that the 
molecule of protoplasm a is blue. But we see at once that 
this is only an artifice, the reasons for which it is not 
necessary for us to inquire into here. It is a fact that the 
blueness is only in the mind of the observer, not in the 
molecules in the brain of A. But how about the other 
properties of this molecule? How about the shape? A 
moment’s reflection will show you that this, too, exists only 
in the mind of the observer; and is produced there by 
rays of undulations of ether being transmitted from each 
point of the molecule (a), and falling upon the retina, 
exciting there again as with color, vibrations amongst the 
molecules of the optic nerve; as before, no picture of the 
molecule has yet arisen, nor again does it arise till the 
motions in the nerve have been communicated to the cells 
of the cortex where, for the first time, a picture of the 
molecule, consisting of a certain outline and surface of an 
octagonal figure b, is formed. 
What is true of color and shape is also true of hardness 
and the other qualities possessed by the molecule. Hard- 
ness is only a sensation derived by touch, and also has its 
origin in the brain of the observer. But after we have ab- 
stracted these qualities from the molecule what remains ? 
That there is something there which excites these sensa- 
tions in us there can be no doubt. Something remains be- SENSORY APHASIA. 
11 
hind ; what it is we do not know. But there is something 
there ; some unknown force or activity you may call it, but 
its nature is unknown. This unknown something we call 
the Reality of the molecule, because it is the molecule as it 
really exists independent of the sensations of color, etc., it ex- 
cites in us. It is called the molecule-in-itself, or the Reality. 
I want you to bear in mind what I have endeavored to ex- 
plain is meant by the Reality of the molecule, in order that 
what will follow may be understood. 
We must still go one step farther. We have learnt what 
is meant by molecules. We have learnt that the “ Realities ” 
of molecules are unknown “ forces.” 
You will remember that it was said that when the 
molecules in the cells in the temporal convolution were 
set into vibration, one with another, that the sound of a 
word arose in consciousness. Now what is meant by 
“ vibration of molecules ”? To answer this we must again 
turn to physiology. Turning again to our diagram, it will 
be perceived that just as the color of a molecule exists only 
in the mind of the observer, so the vibration of these 
molecules is likewise only a sensation, and this sensation also 
occurs in the observer’s brain, when he brings his micro- 
scope to bear on the cells in the convolution. This sensa- 
tion, called a vibration, does not occur in the temporal 
convolution of A, but in the second person’s mind (B). It is 
excited in B by something that occurs in A, just as the 
sensation blue is excited by that something called the 
Reality of the molecule. What is this something which 
creates in the observer the sensation of molecular undula- 
tions ? This in turn is the Reality of the undulations. 
Now the nature of the Reality of the molecules we ad- 
mitted was unknown to us; is the Reality of the undulations 
of the molecules also unknown to us ? My answer is, “ No.” 
It is known to us. What is it then ? It is the word-sound 
we have been in search of. The conscious state which we 
call the sound of a word is the Reality of the vibration of 
the molecules in the cells of the first temporal convolution. 
Such is the explanation which I desire to present to you. 
The data upon which this conclusion rests I cannot enter 12 
MORTON PRINCE. 
into here. I have already done so at length in another 
place, and must refer such of you as desire further proofs of 
this assertion to that work.1 
My intention is to offer you that explanation which in my 
judgment best explains how it is that when the first temporal 
convolution is destroyed word-deafness results. When this 
injury is inflicted, these molecular vibrations, and of course 
the Realities of these vibrations, cannot occur. 
Those of you who have followed me thus far must have 
already perceived that the explanation, which I have endeav- 
ored to make clear, is not limited to the single question of 
aphasia, but is far more wide-reaching and general in its 
principles. It embraces the great question of the relation of 
the mind to the brain, and explains the connection between 
the two. It shows how consciousness arises as the resultant 
of material factors, and how an impairment of the cerebral 
functions means also an impairment of consciousness. It 
shows how the physiological activity of the brain and con- 
sciousness are one and the same thing, and that any imperfec- 
tion in the physical working of the former, means an imper- 
fection of the mind, and an imperfection of the mind means 
an imper fection of the brain. We may say with certainty that 
wherever we meet with an impaired mind, whether that im- 
pairment be either only temporary or permanent, there is also 
some derangement in the physiological working of the 
brain. This theory therefore assumes a practical value. 
Some may be disposed to think that though we may have 
found a mode of explaining the relationship between the 
mind and the brain, still it is only a theoretical question 
without practical utility. To this I wish to make emphatic 
objection. In the first place it is a physiological question, 
and therefore one the elucidation of which enables us to 
understand the modus operandi by which disease of the 
brain is manifested in a disordered mind ; and any thing 
which does this must aid us in the comprehension of mental 
pathology. In proof of this I have only to allude to the gen- 
eral ideas widely prevailing regarding certain functional 
diseases, such as hysteria. 
1 “ The Nature of Mind and Human Automatism.” J. B. Lippincott Co., 
1885. SENSORY APHASIA. 
13 
In former times, not so many centuries ago, either, the un- 
fortunate person afflicted with insanity was said to be 
possessed by an evil spirit, and was loaded with chains, 
cast into a cell, and sometimes even punished with tortures 
that the evil one might be driven out. Improved knowledge 
in physiology and pathology of the body has resulted in the 
scientific and humane treatment of the present day. But 
something of the old ideas still clings to hysteria. An in- 
valid, usually a woman, complains of pain, of suffering, of 
disordered functions of every form. Her character and dis- 
position are changed from what they were. The physician 
examines her, finds no coarse anatomical lesion to account 
for the symptoms, and turns away with the remark : “ It is 
only hysteria.” The patient says she is in pain. The physician 
says again, sometimes even contemptuously : “ It is only 
hysterical.” And every one around the patient says nothing 
is the matter. How different all this becomes when we regard 
every symptom, even the thought which prompts a patient 
to exaggerate her symptoms, as synonymous with disor- 
dered physiological activity ! If we bear in mind that every 
symptom in functional diseases of the nervous system means 
disordered activity of the cells and fibres; that every devia- 
tion in the mental activity of the patient, every change of 
disposition and character, even the absence as well as the 
presence of former modes of thought, means an imperfect 
working of the brain, whether by the inactivity of some cells 
or the too great excitation of others, we shall better compre- 
hend the pathological condition of our patient. 
If space permitted, it would be interesting to notice how 
this conception of the mind and the brain makes thoroughly 
comprehensible many facts hitherto inexplicable, and often 
regarded as mysterious; facts which because inexplicable are 
oftentimes received with credulity. I refer to the in- 
fluence of the mind upon the body both in health and dis- 
ease. The influence of the mind in modifying the physio- 
logical processes of the body is a well-known fact; that 
it can also modify pathological processes of minor grades is 
a fact, which, though tardily acknowledged by the profes- 
sion, is from time to time made use of by empirics and im- 14 
MORTON PRINCE. 
postors for their own material advantage. The well-known 
metallic points of Perkins, which nearly one hundred years 
ago reaped such golden harvests and which now adorn the 
wall of our medical library, as a reminder not less of the 
power of the mind over bodily processes than of the credu. 
lity of human nature ; the bread pills of our fathers ; the 
placebos of modern medicine and the epidemic mind-cure 
of to-day, which like the dancing mania of the Middle 
Ages, threatens to entice the whole population into its folds, 
all attest the power of the mind upon the body. A knowl- 
edge of the nature of the mind and its relation to the body 
allows the intelligent physician to distinguish the true from 
the false, to extend the boundaries of mental action to the 
farthest limit of its own domain, as well as to set restric- 
tions to its encroachments made by shallow and credulous 
believers. 
In attempting to elucidate the connection between aphasia 
and the anatomical lesion of the brain, I have thought that 
the time has come when the physician should not limit his 
investigations to mere broken fibres and degenerated cells, 
on the one hand, nor to mental symptoms, alone, on the 
other, but should ask the nature of the bond between them. g. p. putnam’s sons, printers 
NEW YORK