George W 1856-1940 Jacoby.

Suggestion and psychotherapy online

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large section in the posterior parietal lobes, and,
finally, the island, or insula, which is covered by
the overlapping brain tissue.

The association centres of man materially ex-
ceed in size those of the most highly organized

Centres or systems of speech and their principal
association (after Grasset).

A. Auditorj' centre.

V. Visual centre.

M. Motor centre of speech.

E. Motor centre of writing.

0. Intellectual centre.


animals, even those of the anthropoid apes. To
those centres, above all, man owes his mental supe-
riority, and it is they which are to be considered
most in mental disease.

To-day it may be accepted as a fact that the
cortex of the cerebrum represents a mighty appara-
tus of ganglion or nerve cells — according to Donald-
son's estimate there are nearly ten billions (9,200,
000,000) — the processes of which are connected in
the most intricate manner, both among themselves
as well as with distant parts of the nervous system.
Expressed with more precision, the process of
transmission of sensory impressions and the mo-
lecular movements thereby set into action may be
summarized as follows:

Through the action of external influences, the
elements of the nervous svstem, those neurons of
which we have already spoken, are placed in an
altered state which they then conduct and trans-
mit to other neurons. The excitations consist of
chemical changes which propagate themselves along
the nerve fibres. Unimpaired continuity of the
nerve tracts, therefore, is the prime requisite for this
conduction, the rapidity of which is in nowise in-
fluenced by the intensity of the excitant.


The sensory nerves, or nerves of perception,
which conduct external excitations to the brain
and the spinal cord do not themselves feel or per-
ceive. Neither do the motor nerves, or nerves of
motion, which conduct the excitations from" the
brain and the spinal cord to muscles, glands, and
blood-vessels, themselves induce the movement.
The nerves are simply conductive organs, com-
parable to telegraph wires which connect the send-
ing and receiving stations with each other, while
the apparatus in which the sensation takes place
and from which the motor influences proceed lies
in the brain and the spinal cord. Just as severance
of a motor nerve is followed by paralysis of the
muscle, gland, or blood-vessel which gets its stim-
ulus from that nerve, so will severance of a sensory
nerve produce loss of sensibility in the part of the
body served by that nerve. Similar results also oc-
cur, as has already been pointed out, when the nerve
conduction is interrupted by processes of disease.

The entire central nervous system is made up of
gray and white substance. The gray substance
consists of nerve cells, the white of nerve fibres.
In the large brain (cerebrum) and the small brain
(cerebellum) the gray substance lies on the surface


and forms the cortex, but in the spinal cord con-
ditions are reversed, the gray substance there oc-
cupying the interior and the white substance form-
ing the surface. After severance of the spinal cord
or interruption of conduction in consequence of
destructive processes of disease, all parts of the
body which receive their nerves from the portion
of the spinal cord lying below the point of inter-
rupted conduction are completely paralyzed; not
only have they lost their sensibility, but they cannot
be moved voluntarily.

C. Contents and Course of Mental Activity

The sensory perceptions are the ultimate ele-
ments of psychic action, not susceptible of further
analysis. From them is constructed our entire
ideational life, with the accompanying emotional
tones and impulses of the will.

Animals, too, have sensory perceptions by which
certain reactions and movements are produced in
them. But the manner in which man combines
and assimilates sensory perceptions is what mate-
rially differentiates human psychic action from
apparently similar functions of the animal brain
and places it far above them.


A classic example of that difference is provided
by the history of Clever Hans, the horse which,
it was asserted, had been taught by its owner and
trainer, von Osten-Sacken, to count and calculate
so it could retain in mind and, when questioned,
indicate its own age, the age of its master, and
many other numbers. The explanation of the
horse's apparent mental feats, which a few years
ago created considerable psychologic interest in
Berlin, is due to the psychologist Stumpf and his
pupil Pfungst. Both these gentlemen showed that
Clever Hans, whenever making a calculation, kept
close watch of the expressional movements of the
interrogator, especially toward the end. If, for
instance, the horse were asked to give the prod-
uct of five times seven, it scraped a hoof on the
ground repeatedly until a slight movement of the
head or even a minimal twitch of the eye of the
man gave the animal the signal to cease pawing.
As soon as the horse's eyes were covered with
blinders or it was prevented in some other way
from watching the questioner, its remarkable
mathematical ability was absent. Moreover, the
expressional movements of von Osten-Sacken, or
of any other examiner, were not premeditated or


intentional, as tricks designed to deceive the pub-
lic, but they occurred entirely involuntarily when
the animal reached the figure which represented
the answer to the question.

The five senses furnish to our minds the material
for the interpretation of the outer world; from the
specific qualities of the five separate sensory per-
ceptions we construct the picture of the things
which surround us. In order to measure the in-
tensity of a perception it once seemed simple to
resort to the expedient of measuring the intensity
of the stimulus, on the supposition that a direct
relationship must exist between stimulation and
perception. It soon became evident, however, that
two sense perceptions of equal intensity were not
necessarily produced by external stimuli of iden-
tical strength.

Under certain circumstances, for instance, ordi-
nary daylight will act so strongly on a very sensi-
tive eye as to cause it to close, whereas only direct
exposure to the sun's rays will bring the same re-
sult in a less impressionable eye. Intensity of
stimulation and intensity of perception, therefore,
are not directly comparable. In the same connec-
tion we must also consider excitability or sensi-


bility, which varies in different persons, and even
in the same person at different times. From that
we derive this law:

The greater the sensibility, the weaker will be
the stimulus, and the lower the sensibility, the
stronger must be the stimulus necessary to produce
the same perception.

We are led to another law by these considerations:

We all know that in the stillness of the night our
attention is attracted by noises which in the bustle
of day remain unnoticed. A clock ticks with the
same intensity at all times, but the ticks are per-
ceived by us in varying degree at various times.
From that we learn the same stimulation will be
perceived to a greater or a slighter degree, or not
at all, according to circumstances. The general
law which may be formulated as to such variations
of perceptions is this:

The weaker the already existent stimulus, the
smaller may be an added stimulation in order to
be perceived; the stronger the stimulus which is
already present, the greater must be the added
stimulation to be perceived.

Finally, because of its important bearing on the
adjustment of our sensory apparatus, we must give


consideration to this fact: Only within certain con-
fines can we have definite sensory impressions.

There is a so-called excitation threshold below
which we are unable to perceive anything, and
above which no intensification of external excita-
tion can cause any increase of perception. That
excitation border is not equally high in all persons,
since people differ, some being of a delicate and
others of a coarse organization; nor is the excita-
tion border always the same in any one person, as
we are able to adjust ourselves in diverse ways to
the reception of stimuli. There is probably no
gradation which can render one more deficiently
impressionable to external stimuli than that of
augmenting concentration of attention.

It is recounted of a great poet that he wrote
dramas while surrounded by his boisterous chil-
dren. The threshold of excitation for auditory
stimulation in him was so high that the noise of
his immediate surroundings did not become a con-
scious impression.

Who has not had the experience of being so
deeply immersed in an interesting book as to be-
come insensitive to many external sensory stimuli,
which, because of his undivided and increasing at-


tention, did not succeed in passing the threshold
of consciousness? On the other hand, we know
that the most intense light blinds us, the most in-
tense sound deafens us, and, therefore, that a sen-
sory stimulus above the upper boundary of excita-
tion can cause no increased impression.

Within the limits of this book we cannot enter
upon the elucidation of all the details of those
processes by which impressions of sight, hearing,
taste, smell, and touch are conveyed to the brain.
It would lead us entirely too far afield were w^e to
take up the theories of waves of light and sound,
or to attempt a description of the receiving and
conducting apparatus of the two most important
sensory organs, those of sight and hearing, or of
the method in which the various qualities of light,
sound, the body sensations, etc., are produced.

Still we cannot refrain from calling attention to
a very interesting and most appropriate diversity
in the arrangement of our auditory and visual ap-
paratus. This lies in the fact that tone percep-
tion ceases simultaneously with the cessation of the
tone-producing cause, while a visual perception out-
lasts its causal excitation. The ear is equipped
with a mechanism similar to the tone-damper in a


piano, but for which the continued vibration of the
drum of the ear would cause an uninterrupted and
ultimately unendurable noise. On the other hand,
light impressions upon the eye persist after the
stimulus is removed, a fact which is proved by the
well-known experiment of whirling a glowing coal
rapidly in a circle with the result that, instead of a
broken line, a complete fiery ring is seen. Further-
more, the fact of after action of visual excitation
explains the occurrence of so-called persisting im-
ages or after-sensations. If we gaze directly at the
sun for a moment when it is setting and then at
the ground or the gray wall of a building, we see
distinctly at the latter point of fixation an image
of the disk of the sun. Similar "after images"
arise under other conditions and may be studied

The phenomena of so-called secondary sensory
impressions is equally worthy of attention. Often
a sensory impression produced by external stimu-
lation causes a simultaneous impression within the
domain of some other sense for which a corre-
sponding external impression is lacking. For in-
stance, I may hear a loud report and at the same
time see a flash of light, although there may be no


flash, or, vice versa, I may see a bright flame flash
up and with it hear a report, although there be no

In such cases there is an unusual transfer of an
excitation from one sensory field to another, an
apparent contradiction of the above-mentioned law
of specific sensory energy. Under normal condi-
tions such a transfer would hardly occur, because
one sense organ cannot perform the function of
another. Excitation of the optic nerve always will
excite an impression of light, but never a percep-
tion of sound or touch; excitation of the auditory
nerve always produces only perception of sound,
and never of smell or taste. A secondary sensory
impression, therefore, is produced not by an ex-
ternal excitation, but by a perception which un-
doubtedly is of morbid nature. That leads us into
the realm of sense deceptions, which will be con-
sidered later.

Here it will suffice to say that the lingering of
sense impressions has nothing in common with
sense deceptions, and that neither the memory
pictures which remain as a result of sensory per-
ceptions nor the imaginary pictures which may be
voluntarily aroused by their aid can in any way


be classed among such sense falsifications. All
those phenomena are indications of healthy sen-
sory, i. e., mental, action, just as, for instance, a
stick which is immersed in water appears to every
normal eye to be broken, and a black square seems
smaller than a white one of exactly the same size.

The brain cortex, as we have already seen, is
that part of the central nervous system which is
most distinctly influenced by the experiences of the
individual. It serves for the adaptation of the in-
dividual to the conditions of life in which he is
placed. What constitutes the processes which take
place in the brain is not yet clear. With Du Bois-
Reymond, we must acknowledge especially that
we know nothing of the manner in which nerve
tracts are stimulated by ideational processes, nor
how conscious perceptions are produced in our
brain by external sensory stimuli.

Nevertheless, the results of modern scientific in-
vestigation force us to assume that the brain cor-
tex possesses in a well-developed degree the ability
to retain impressions which it has received, and,
by means of numerous association tracts, to com-
bine them with other impressions. We shall have
to assign to the brain cortex also the capability of


transforming the excitations which it has received
into movements, or of preventing the occurrence
of such movements. A short survey of investiga-
tions teaches us these facts:

As a result of the varied stimulations which the
external world produces upon our sensory organs,
certain regions of the brain cortex become excited
and give rise to perceptions of sight, hearing, taste,
smell, or touch, the last class being further sub-
divided into perceptions such as of temperature,
pressure, etc. The perceptions which arise in ac-
cordance with the excitation of the cortex pass
away with the disappearance of the excitation.
The cortex, however, retains a record of the ex-
citation which persists as a memory picture, or
image. That record for the time being we fail to
notice, but later, when the same perception or a
similar one arises, we remember the previous per-
ception — that is, we remember that we have seen
the same object, or heard the same tone, or per-
ceived the same odor before. All our concepts are
memory pictures of perceptions. Congenital con-
cepts do not exist. The memory picture probably
is not bound to those cells in which perception
arises; it is better to assume that the excitation




Diagram representing the action of the nervous sybiein.

C. Brain cortex. 5. Centre for sight. P. Centre for pain perception.
MC. Motor centre. He. Centre for hearing. SP.c. Spinal
cord. G. Gray substance (ner\-e ceUs). W. White substance
(nerve fibres), pc. The nerve tracts making up the posterior
column. AC. The nerve tracts making up the anterior column
af. Association tracts. E. Eye. A. Ear. H. Hand. m. Mus-
culature. L. Source of light, mn. Muscle or motor nerves, vn
Nerve of vision, an. Nerve of hearing.

passes over from the cells of perception to the cells
of memory.

If a certain part of the cortex of the occipital
lobe in man becomes diseased, the patient no
longer recognizes the most ordinary things about


him unless he takes them in his hand and touches
them. He is "soul-blind," and yet his eyes func-
tionate in a perfectly normal way, for he follows
objects with his vision and goes out of the way of
obstacles in his path. That fact makes it extremely
probable that sensory impressions and memory
pictures are deposed in different nerve cells of the
brain cortex. Otherwise it would be inexplicable
how, notwithstanding the orderly operation of sen-
sory impression, amnesia can persist.

Through a new combination of old memory
images, pictures of the imagination arise. These
play an important role not only in artistic activity
and in scientific work, but also in every-day life,
since every action or occurrence is associated with
a consideration of the possible results.

The precision of an idea is dependent on the
intensity, the duration, and the frequence of the
occurrence of the sensory perception which forms
the basis of that idea, and on the time which has
elapsed since its last occurrence. If the same or
similar sensory impressions do not again and again
rivet the material alterations which have taken
place in the memory cells, then, in consequence of
metabolic influences, these same changes will dls-


appear. The molecular changes in the nerve cells
which are not in any way perceptible by means of
any of our present aids, become blotted out and
the memory pictures are forgotten. The same
process, amnesia, may also occur, as we have al-
ready mentioned, in consequence of disease in cer-
tain parts of the brain cortex. To understand
how it is possible that the sensory apparatus may
functionate normally while at the same time no
memory picture may remain for any former sen-
sory impression of the same or a similar kind, we
must constantly keep clearly in mind the differ-
ence between cells of sensation and cells of

The sequence in which concepts occur or the
path which excitation takes in the brain cortex is
determined by the associative connection which
exists among the memory cells. The connecting
tract between memory cells becomes passable as
a path of least resistance in varying degree, de-
pending on the frequence, the persistence, and the
unison of excitation of the cells connected by the

Under certain conditions "passable" connect-
ing tracts — that is, tracts which are frequently ex-


cited — functionate entirely automatically. A pian-
ist, for instance, will be able to execute faultlessly
a piece which he has played frequently, and yet at
the same time his mind may be absorbed in some
subject entirely unrelated to the music. In the
same way are explained the dangerous feats not
infrequently accomplished by sleep-walkers, such
as climbing over roofs, walking upon window sills,
etc., feats which the performer when awake could
hardly have achieved. In such persons there is,
on the one hand, an exclusion of the consideration
of the danger which is associated with such actions,
while, on the other hand, the associative connect-
ing tracts in the somnambulists are sufficiently pass-
able to enable them unconsciously to carry out the
movements necessary to prevent their falling or
coming into contact with obstacles.

Other important elements in the current of as-
sociation of ideas are the distinctness of the mem-
ory picture on which recognition depends, the emo-
tional tone which accompanies the concepts and of
which we will speak later, and the extremely vari-
able influence of mutual retardation or acceleration
which the memory cells exert upon one another.
The phenomena already considered must remove


smy doubt that the processes of the mind are func-
tions of the cerebral cortex. The sensory impres-
sions which bring our minds into relationship with
the external world and form the basis of all our con-
cepts leave in the cortex actual ** imprints," mole-
cular alterations of the nerve cells, which in turn
incite other changes or movements, in the nervous

Psycho-physical parallelism is the term used to
designate these close relations between the psychic
processes and the material changes in the nervous
apparatus, especially in the brain cortex — the re-
lationship, in other words, between the action of
the mind and the bodily processes. This psycho-
physical parallelism has been very carefully inves-
tigated by Bumke, and his conclusions have been
published in a very interesting dissertation. He
arrives at this conclusion:

"While it is true that an impression cannot be
measured, nor can it be said that it is so and so
much greater than another impression, neverthe-
less many phenomena of mental life are open to
exact investigation because every mental process
is, after all, produced and excited by physical ex-
citations which come from the outside, and be-


cause those processes almost as regularly finally
lead to bodily expressions, to motor discharges
which we designate as expressional movements.
We are able to measure the two end links of this
chain; we can estimate the stimulus by means of
which the processes of consciousness are uniformly
aroused, and we can analyze with precision the
bodily reactions which are observed to accom-
pany or to follow with regularity the course of
these physical processes."

Bumke calls special attention to the fact that each
of the various emotional states is accompanied by
a variation in the size of the pupils, by a distinctly
measurable variation in the rhythm of the heart
and of respiration, and by corresponding changes
in the blood pressure. Such expressional move-
ments, taking place involuntarily, furnish an ex-
planation for "mind-reading." The mind-reader,
on the one hand, depends on the fact that the mere
expectation of having our thoughts read leads to a
corresponding action of our muscles without that
action being influenced in any way by the will,
and, on the other hand, he must possess extraor-
dinary skill in recognizing minimal changes of ex-
pressional movements, especially those regulated


by the facial muscles. A slight movement of the
•head, a glimmer in the eyes, a deep breath, reveals
to the mind-reader, even though there be no con-
tact between him and the object of his experiment,
that the hidden thought is upon the verge of dis-
closure. Similar expressional movements which will
be interpreted as evidence of dissent instead of as-
sent, plainly indicate that he is following a wrong
track and that the solution of the problem must be
sought in another direction. The trick of Clever
Hans, to which we have already alluded, depends
entirely on such skill. The occurrence of such ex-
pressional movements may easily be demonstrated
in a rough way by the following experiment: Hold
the free end of a string having a weight attached
to the other, or the free end of a watch and chain,
between thumb and forefinger, so that the weight
will swing freely and constitute a pendulum. Bring
the weight into a state of rest. Concentrate your
thoughts upon the motionless pendulum and keep
thinking, and saying to yourself, "Now the weight
will move forward and backward"; with proper
concentration of mind, the weight will, as a result
of minimal, unconscious, and involuntary muscular
movements, move to and fro. Then change your



thoughts to "the weight will now move from side
to side," and in a moment the direction of the

Experiment showing influence of concentration of
thought upon muscular movements.

movement of the weight will have changed to ac-
cord with the new train of thought.


For every sensation, for every idea, there is a
corresponding brain vibration, a movement of the
molecular atoms in the brain. Furthermore, every
brain vibration causes a perception, an idea,
whether we be in a waking state or in a dream.
There can be no thought without corresponding
vibration of the brain. All our perceptions, with-
out exception, take root in the brain. I may burn
my foot, prick my finger, inhale a fragrant odor,
or eat a palatable dish, and in the specific instance
the impression apparently is perceived in the foot,
the finger, the nose, or the mouth, but it really has
been transmitted by the nerves to the brain, and it
is that organ which causes the perception.

Even more remarkable is the fact that an ex-
tremity need not be present at all, and yet we may
believe that we have feeling in the missing member.
Often a person whose arm or leg has been ampu-
tated has sensation in^he missing limb long after

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Online LibraryGeorge W 1856-1940 JacobySuggestion and psychotherapy → online text (page 3 of 18)