_THE CIRCULATION OF THE BLOOD IN THE BRAIN DURING EMOTION_
I
When we have drawn on a pair of very tight gloves, we feel, if we
pay attention, a slight throbbing in the fingers, corresponding to
the rhythm of the cardiac pulsations. This throbbing arises because,
by every contraction of the heart, one hundred and eighty cubic
centimetres of blood--that is, about as much as can be contained in an
ordinary drinking-glass--are driven out of the cavity of the thorax.
As this wave of blood penetrates the various organs of the body they
swell, as is the case with the arteries which dilate at every pulsation
and then resume their former volume. When the hands are unconfined
we notice nothing, but if we squeeze them into gloves, or our feet
into tight shoes, we feel something beating in fingers and toes. This
is the blood gushing in, and as the skin cannot yield as in ordinary
conditions, the extremely delicate nerve-filaments which branch into it
are pressed at every pulsation. If our finger swells from a whitlow,
an inflammation, a knock or a burn, immediately the physiological
pulsations, unnoticed before, become continuous, causing an acute,
stinging pain. The blood flows more abundantly to the inflamed part,
the elasticity of the tissues diminishes, the skin becomes more
unyielding, an increased pressure on the nerves ensues, and these,
rendered more sensitive through the injury, communicate a painful
sensation to the brain which pricks unceasingly, keeping time with the
rhythm of the heart.
In no organ is the supply of blood so abundant as in the brain; it is
sufficient to state that one-fifth of the blood in our body goes to
the head. Often, when lying on our side with our cheek on the pillow,
we hear the waves of blood passing from the heart to the brain. The
arteries, in pulsating, raise the skin, and this movement occasions a
slight friction against the pillow, which then propagates itself to the
ear. But it is not the beating of the blood against the walls of the
vessels, as we feel it on the carotid artery of the neck, or on the
radial artery of the hand and elsewhere, which most interests us. A
whole world of important facts in the physiology of the emotions and in
the circulation of the blood would still be unknown if physicians were
still only feeling the pulse, as has been done from the earliest days
of medicine until now.
With the old methods we should never have succeeded in observing the
spectacle of continuous and ever-varying changes which the movement of
the blood operates in the brain, the hand, or the foot.
The physiologist used to be like a man wishful to study the life of a
city, and only able to do this by looking down from a terrace at the
coming and going of the crowd, the perpetual stream of people in the
street. Only of late years have we succeeded in penetrating into the
houses by the roof, in spying out the inner life of each family, in
studying the irrigation of the organs by the blood while they are at
work or in repose.
The pulse in the finest branches of the vessels and in the inward
recesses of the organs is such a subtile, delicate phenomenon that we
need the assistance of special instruments to intensify it before we
can study it. I shall not do as many naturalists do, who think they
should conceal the artistic side of their investigations from the fear
of desecrating science.
I know that every experimental work possesses an interesting side,
which is quite lost owing to the aridity and severity with which
scientific treatises are written, and I therefore abandon myself to the
recollections of my investigations, careless of following the style of
popular scientific books.
II
The first work which I published upon the circulation of blood in the
human brain brings sad recollections to me. It was in June 1875 that
my friend, Professor Carlo Giacomini, invited me to visit one of his
patients in the syphilitic ward. It was a peasant woman, thirty-seven
years of age, who, after having borne six children, had been infected
by her husband with the most terrible disease to which a mother may
fall a victim. For nine years the deadly poison had raged in her bones,
and, with only short intervals of respite, had corroded a great part of
the skeleton and destroyed the upper part of the skull from the nasal
bones to the occiput. Medical art had proved powerless to arrest the
disease. When Professor Giacomini took the woman out of pity into the
hospital, her face was disfigured, her body was covered with sores and
scars, the skin of the head was detached in various parts, the corroded
skull had a blackish colour, like dead bones encased in living flesh.
It was after hearing from this unhappy woman the story of her
misfortune, and during the intense emotion which pity for her aroused,
that I saw for the first time, through the fissures of the decayed
bones, the movement of the uncovered brain. Even to-day, eight years
later, when I think of that moment, a shiver runs over me as it did
then.
The patient recovered strength after energetic treatment, and was
able to walk about the garden after a few weeks. It was then that we
began to study her brain. I shall not describe the various instruments
we constructed, but only remark that we lost much precious time with
different attempts, and when we were at last ready, the most favourable
time was already past, the wound was covered with a thick scab, which
dulled the pulse of the brain. Nevertheless, we made some rather
important observations, the results obtained being the most complete up
till that time in the physiology of cerebral circulation.
In order to give an instance of the delicacy of the apparatus, and
to prove the accuracy of our investigations, I mention the following
circumstance. One day we were assembled in the laboratory of Professor
Giacomini, intent on studying the brain of the patient, who was sitting
in her arm-chair, and seemed absent-minded. There were a few spectators
in the room, who were told to remain quietly behind the patient’s back.
In solemn silence we observed the curve marked by the cerebral pulse
on the registering apparatus. Suddenly, without any external cause,
the pulsations rose higher, and the brain increased in size. This
striking me as strange, I asked the woman how she felt; the answer was,
well. Seeing, however, that the circulation in the brain was very much
altered, I examined the instrument carefully, to see whether it was all
in order. Then I asked the patient to tell me most minutely what she
had been thinking about two minutes before. She said that, as she had
been looking absent-mindedly into a bookcase standing opposite to her,
she had caught sight of a skull between the books, adding that it had
frightened her by reminding her of her malady.
This poor woman was called Margherita; she was rather timid, but
willingly allowed herself to be examined and studied, full of
confidence in us, who vied with each other in showing her polite
attentions. Her children often visited her, but she was ashamed to go
back to her native place with her terribly disfigured face, preferring
to remain away from her family and perform the duties of nurse to the
other invalids in the hospital. After many years I felt a wish to see
her again. As I pressed her hand to encourage her, she told me that she
had at last given up the wish to die.
III
Chance furthered the continuation of these observations, new
opportunities for this study soon offering themselves in Turin and
elsewhere. In the lunatic asylum I found a boy a portion of whose skull
was wanting. In the year 1877 I came across a man in the hospital of
San Giovanni, who had an opening in his forehead which seemed made on
purpose for examination; and finally, last year, I was able to repeat
and conclude my investigations on a perfectly healthy man who had also
a hole in his skull. As yet I have had no opportunity of publishing the
observations and experiments made on this man.
How anxious and agitated we are when we enter upon a new field of
science; when, at every step, the doubt arises whether some important
phenomenon may not have escaped us! How we are tormented by the fear of
not being able to face the most vital questions, nor to find out those
phenomena most fruitful in results and most subtile! What trepidation
overcomes one before one writes down even a few lines in the book of
science!
Even amongst physicians it is not easy to find any who are able to
write down the history of any fact or observation. The majority
of them only know how to relate things in the same dogmatic words
with which they are described in treatises, and only a few take the
trouble to examine the development of an idea. And yet, in the study
of human nature there is nothing more interesting than to follow the
different phases of a problem, to see whence a thought arose, to know
the first means by which nature was interrogated, then the sudden
changes of method, the incidents, the errors and corrections, and at
last the victory which crowns our labour and wins a fact for science.
I believe if it could be seen near at hand how a research develops in
the laboratories, the followers of the experimental sciences would be
greater in number.
It is a work of patience. The only difficulty consists in gradually
learning the language of Nature, in finding out the way to interrogate
her and compel her to reply. In this struggle, in which we, humble
pygmies, fight continually in order to wrest from Life its secret,
there are moments of intoxicating emotion, rays of light amongst the
shadows, which excite the imagination of the scholar and the artist.
IV
The second case, which I studied in company with Dr. Albertotti, was
that of a boy eleven years of age, with an agreeable physiognomy and
very beautiful physical proportions. He had scarcely reached his second
year when he fell from a terrace, fracturing his skull and causing a
severe concussion of the brain. After two years and a half he began to
suffer from epileptic fits, and later, signs of insanity appeared which
obliged his relatives to send him to the lunatic asylum in Turin.
When I saw him in February 1877, he had a large opening in the skull,
a little above the right eye, and covered with skin; it was as big as
the palm of his hand, and in the pit of it one could feel the pulsing
of the brain. The terrible fall had for ever arrested his intellectual
development. He was gay, smiling, and lively, like a big baby, but he
could not speak. It was a saddening circumstance that in the midst of
this ruin of his mind one single higher idea had remained, a remnant of
his earlier intellectual life, a motto which he constantly repeated: 'I
want to go to school.’
Of all the human cases I have studied, the observations made on this
boy gave me the greatest trouble. As I had to do with an idiot, the
least obstacles became great difficulties. No apparatus could be
applied without his becoming restless, snatching it from his head, and
breaking everything which fell into his hands. I had to confine myself
to a few observations which could be made by surprising him while
asleep. But he did not sleep regularly; I have often found him still
awake, even when I made my nightly visit at a very late hour. It was
more than sleeplessness, it was a nocturnal excitement, which presaged
the storm of an epileptic attack. I have seen him the victim of the
most terrible fits, while, on the nights following, his sleep was so
deep as to leave one in doubt whether it was a natural phenomenon.
In the period of exhaustion and stupor, the blood-vessels of the brain
seemed to relax, and at every contraction of the heart the pulsations
became stronger. A faint noise which did not wake the patient was
enough to produce a change in the brain and a more abundant gush of
blood. It sufficed to touch him, or to approach him with the lamp:
immediately, the volume of the brain increased, and a great elevation
appeared in the curve of the pulse.
Whenever we called him by name, it seemed as though an impetuous wave
of blood rushed into the brain, causing the convolutions to swell. As
this was invariably the case, there could be no doubt that the brain
was still sensitive to the impressions of the external world, even
during a heavy sleep. When the patient was shaken till he woke, I could
see the circulation changing little by little, as though the material
conditions of consciousness were being restored.
He often spoke a few indistinct words, opened his eyes, or moved his
hands, and then slowly fell back into the previous stupor, while we saw
the pulse grow weaker, the brain decrease in volume, the rhythm and
force of the breathing change.
It was one of the most interesting sights to observe in the stillness
of night, by the light of a little lamp, what was going on in his
brain, when there was no external cause to disturb this mysterious life
of sleep. The brain-pulse remained for ten or twenty minutes quite
regular and very weak, and then began suddenly, without any apparent
cause, to swell and beat more vigorously. Then the agitation subsided
and there was a second period of quiet; then came stronger blood-waves
which flooded the convolutions, raising the height of the pulsations,
which were automatically marked by the apparatus applied to the brain.
We scarcely dared breathe. The one who was observing the instruments
communicated with the other, who was watching over the patient, by
pressing his hand. Looks full of interrogation and wonder would meet,
and exclamations had to be forcibly repressed.
Did dreams, perhaps, come to cheer the repose of the unhappy boy? Did
the face of his mother and the recollections of his early childhood
grow bright in his memory, lighting up the darkness of his intelligence
and making his brain pulsate with excitement? Or was it perhaps only a
morbid phenomenon, like the jerky movements of a broken wheel, or the
index of a machine out of order, swinging idly to and fro? Or was it
an unconscious agitation of matter, like the ebb and flow of an unknown
and solitary sea?
What a contrast between the pleasing emotion which this work roused in
us and the sadness of the surroundings! Even that quarter of the city
in which the asylum is situated has something characteristic about it,
which De Amicis compared to the silence and mystery of an Oriental
town. Sometimes, when late on winter evenings I made my way along the
deserted streets, I could not even hear my own footsteps as they fell
noiselessly on the snow. In the long dormitories of the hospital the
dim light of the lamp could not dissipate the gloom in the remote
corners of the room. However much care I took to glide softly through
the room, in order not to disturb the sleep of those poor wretches,
many were yet sitting upright in their beds, with staring eyes, seeming
to await my coming and ready to shriek at me as I passed. Others,
uncovered and naked, in spite of the winter cold, gazed at me with
empty, fixed eyes; while others again, bound, to prevent their injuring
either themselves or others in their mad fury, followed my steps with
wild glances.
What a cheerless sight for a physician, and for me, who came amongst
them to study the brain. At the end of these rooms was a little
chamber in which I watched my subject. Often I had to interrupt my
investigations, and, lamp in hand, go to the most noisy, begging,
imploring them to be silent for one minute. It was a waste of breath.
Caresses, presents, threats--all were alike of no avail. And when, late
at night, discouraged at the failure of my experiments, I left that
abode of pain, they were still awake, staring at me with the fixed,
impenetrable gaze of a sphynx or the malignant smile of a demon; and
when I stepped out into the desolate street again it seemed to me as
though I had just escaped from a vision of spectres.
V
Physiologists may wait a long time before finding a more suitable
subject on which to study the circulation of blood in the brain than my
Bertino. He had a hole in the very middle of the forehead, that seemed
made to allow one to look into the skull as an old Greek philosopher
once wished to do with the human heart.
To my regret the man only sojourned for a very short time in Turin, and
I could only study him during one week. He was a sturdy mountaineer,
who suffered from home-sickness, and seemed to be ashamed of his
disfigurement. In July 1877, as he was working under the belfry of his
village, he was struck on the head by a brick which a mason, working
near the roof, at a height of fourteen metres, let fall out of his
hand. Bertino fell to the ground as though struck by lightning. He
told me that he remembered nothing of it all, not even the blow he
had received, and that he regained consciousness after one hour. The
earliest recollection which he preserved of the accident was of the
moment before the blow. He remembered that he was standing under the
belfry watching a comrade dipping bricks into water; then came a period
of darkness in his mind, and when he came to himself again he found
himself, to his astonishment, in bed, while a surgeon held a watch
before him and asked him what time it was. From that moment his mind
had been quite clear. The terrible blow made an opening of the size of
a shilling in the middle of the forehead. When the splinters of bone
had been removed, the brain was seen through the opening, uncovered and
pulsating. After having been twenty-four hours in bed, he came on foot
to Turin. My friend, Dr. De Paoli, took me to see him. The patient had
lost nothing of his power of movement, of his intelligence, his speech,
or his memory; he was only very much afraid, and had a perpetual
expression of distrust and timidity, even about the most unimportant
things, which he tried in vain to conceal.
I must remark that in fractures of the skull the time favourable
to study is very short. Large wounds admit with difficulty of the
application of the instruments; the smaller ones are better adapted,
but they close much sooner from underneath by cicatrisation. When I
made the acquaintance of Bertino, the best time was already past;
nevertheless the investigations which I made on him are, according to
the judgment of competent physiologists, the most complete that have as
yet been published.
Eighteen months later I wrote to him, asking him to come to Turin, as
I wished to see him. He came at once, and told me that if he had not
escaped from the hospital he would have died of melancholy; that he had
not been able to bear being in rooms full of dying people, while at
home wife and children and fields were awaiting him. The opening in the
skull had closed, and the movements of the brain were no longer visible.
VI
Let us now see how the brain writes when it guides the pen itself. I
have already collected a few volumes of these autographs, from which
I here give a single line as an example, written by Bertino’s brain
in the night of September 27, 1877. He was lying on a sofa. I had
applied the apparatus which traces the movements of the brain to his
forehead, and watched the pen writing on the cylinder while I waited
for him to fall asleep. At first the pen traced large undulations, a
certain sign of great restlessness in the blood-vessels of the brain;
the pulse-lines were considerably modified from time to time in form
and height, and this, although profound silence reigned. I might have
asked him what he was thinking of, but I did not do it, as I wished
urgently to see him fall asleep. At last the undulations began to
decrease, becoming lower and less frequent, sometimes separated from
each other by long periods of repose, like a lake gradually growing
calm, but upon which from time to time a little wave ripples, troubling
the smooth surface. At length Bertino fell asleep. Consciousness was
extinguished, the troublous thoughts of life had ceased, only the last
sentinels of the nervous system were still vigilant. At the slightest
noise a wave of blood disturbed the surface of the brain. If the
hospital clock struck the hour, or someone walked along the terrace, if
I moved my chair, or wound up my watch, or if a patient coughed in the
next room--everything, the slightest sound was accompanied by a marked
alteration in the circulation of the brain, all immediately traced by
the pen which the brain guided on the paper of my registering apparatus.
[Illustration: FIG. 1.--PULSE OF THE HUMAN BRAIN DURING SLEEP]
After an hour and a half, when I saw that Bertino was breathing quite
calmly, with the rhythm and in the characteristic manner of a sleeper,
I rose with great caution, approached the pillow on which he had laid
his head, and at that point in the curve where is the sign of the
arrow, ↓, I called him gently by name, 'Bertino.’ He did not move or
answer. If we examine the curve in fig. 1, we find that even before
the sign, ↓, four pulsations are somewhat higher than the preceding
ones. This first increase in the volume of the brain is due to the very
slight noise which I involuntarily made with the chair on rising to
approach Bertino.
After calling him by name, the brain wrote three pulsations which
have the form of the preceding ones; then the pulse changed, and
the pen traced four pulsations, one higher than the other. This is
the beginning of what I have called an _undulation_. During the
next pulsations the pulse-line gradually falls until it reaches the
previous height. In comparing the form of the pulsations at the
beginning of this curve with those at the end, we see that even this
very slight emotion, which was not able to interrupt sleep, yet
sufficed to produce a great modification. The pulse is stronger,
its form tricuspid. We physiologists would say that, from being
anacrotic, it had become catacrotic. But the variations which appear
in the circulation of the brain during fear are far greater. The
reproofs and threats which I uttered to Bertino when he was hindering
my experiments by moving his head or hands, the disagreeable things
which I sometimes purposely said to him, were always followed by very
strong pulsations; the brain-pulse became six, seven times higher than
before, the blood-vessels dilated, the brain swelled and palpitated
with such violence that physiologists were astonished when they saw the
reproductions of the curves, published in the tables of my researches
on the circulation of the brain.[13]
[13] _R. Accademia dei Lincei_, vol. v. series 3a; _Nuova Antologia_,
March 1881.
VII
In Canada, in 1822, a soldier called Alexis St. Martin was shot at
from a short distance. The bullet penetrated the abdomen, perforating
the stomach. In a few months, thanks to the treatment of Dr. Beaumont,
he was completely healed, only an opening remained in the abdominal
walls through which the processes in the stomach could be seen.
Several physiologists in America had thus the opportunity of observing
the stomach during digestion by looking into its cavity as through
a window. The investigations made on this soldier resulted in the
statement that the stomach becomes redder as soon as digestion begins.
Later, physiologists showed, by other observations, that the salivary
glands grow red during mastication, and that the muscles contain more
blood when they are at work a long time. We all know that the eyes of
anyone who works long become red, that the feet swell after a long
walk, and that, in fencing, the muscles of the arms and the hand which
grasp the weapon grow thicker.
From these facts we may deduce a law which has no exceptions, namely,
that blood is more copiously supplied to an active organ.
The organs of our body are like so many little machines, to which
one must furnish fuel if their working power is to be increased. But
whereas, in ordinary mechanisms, it is a strange hand which keeps up
the fire and directs the movements, our organism is so perfect that
in it all apparatus regulate themselves with the greatest harmony of
object. In the working muscle the blood-vessels expand, thus more
easily to transmit the fuel, and in order that the muscle may convert
the chemical force of food into a contraction. In the digesting stomach
the circulation is more abundant, because the glands must secrete a
greater quantity of juice, the little veins absorb the fluids contained
in the stomach, and the muscles contract more quickly in order to mix
the food.
Our organism, like all working machines, not only consumes and destroys
fuel, here represented by those elements which constitute the blood,
but through its activity it also wastes those parts of the body which
represent the wheels, axles, hinges, and other parts of a mechanism. At
every contraction of the muscles, at every sensation in the brain and
nerves during any mental work, there is a wasting of the organs. The
blood, flowing continually through all parts of the body in order to
feed the flame of life, sweeps at the same time the most remote corners
of our organism clean of soot, or the remains of combustion. The
vessels become relaxed and expand. Nutrition and organic change become
more rapid, the nutritive fluid trickles more easily through the walls
of the vessels, the blood flows more quickly, and carries everywhere
along with it all the waste products in order to bring them to the
kidneys. These purify the blood, and expel, with the urine, the scoriæ
of the working organism.
We have seen how the circulation in the brain is accelerated during
mental activity, emotion, and in a waking condition; we shall return to
this subject in the next chapter, and study more nearly the mechanism
by which such variations are produced in all the other organs of the
body. This subject is of great importance to physiologists, because
in no other way can the slender link which connects psychological
phenomena with the material functions of the organism be rendered more
evident.
It suffices to increase or diminish in a slight degree the rapidity
of the blood penetrating to the brain, in order to cause an immediate
change of our 'ego.’ The equilibrium of the molecules in the organs
where consciousness has its seat is greatly disturbed by causes which
scarcely affect the functions of other parts of the body; because, in
the brain, nutrition is more active, and the state of the substances
composing it more unstable. The sublimity of psychic phenomena has its
root in the greater complication of the material facts by which they
are originated. If I were asked which of the functions of the organism
were most sensitive to the slightest organic change, I should, without
hesitation, answer--_consciousness_.
VIII
Often, in contemplating the brain of my patients, pondering over its
structure and functions, and seeing the blood coursing through it,
I have imagined that I might penetrate into the inner life of the
brain-cells, might follow the movements which agitate their minute
branches in the labyrinth of the nerve-centres; I have thought I might
learn the laws of organic change, the order, harmony, the most perfect
concatenations; but my mind might work as it listed, and imagination
seize the reins, I never yet saw anything, not the faintest gleam,
which gave me hope of penetrating to the source of thought.
During my investigations I have discovered the mechanism with which
nature provides for a more rapid circulation of blood when the brain
must enter into activity; I was the first to admire some of the
phenomena in which the material activity of this organ reveals itself;
but although I have scrutinised the functions of the brain with the
most exact methods of physiological investigation while it was pulsing
under my eyes, while ideas were seething in it, or while it rested in
sleep, the nature of the psychic processes still remains a mystery.
We all believe that the faculties of the mind are the fruit of an
uninterrupted series of natural causes, of physical and chemical
actions which lead from the simplest reflex-movements, step by step,
to instinct, reason, sentiment, and will; but as yet nothing has been
found which might lead us even to suspect, much less to comprehend, the
nature of consciousness.
We attain our firmest convictions in the domain of positivism, not from
the narrow field of physiology but from the whole kingdom of science.
We imagine that the impressions of the external world form a current
which penetrates the nerves, and, without either abatement or check,
diffuses and transforms itself in the centres, finally reappearing
in the sublime form of the idea; this is the notion of the soul held
by the philosophers of remote antiquity; this is the base of modern
psychology.
We may suppose that thought must be a form of motion, because the
science of the present day demonstrates that all intimately known
phenomena may be reduced to a vibration of atoms and to a displacement
of molecules.
I can think of my brain by the analogy which it must have with that
of another; but the bridge which leads me from external to internal
observations I cannot find; between physical and psychic phenomena
there is a gulf which we cannot pass.
The soul was regarded by the ancients as a harmony. But how this
sublime harmony of imagination, of memory, of the passions, and of
thought, results from the vibration of the molecules constituting the
brain, no one knows. The road which connects psychic facts with the
transformation of energy has not yet been pointed out.
I know the chemical transformations which give rise to the mechanical
work of the muscles of my hand in writing, but I do not know the
processes of my brain which thinks and dictates.
Many have thought and asserted, because the muscles and glands of
our body grow heated by their work, that the brain and nerves also
grew warm during activity. For my part, I doubt the accuracy of the
methods used in these experiments, nor shall I be convinced unless it
be clearly shown to be a fact. As the nature of the chemical processes
taking place in the brain is totally unknown to us, it may be that the
brain grows colder during activity. The question can only be decided
when we succeed in eliminating the serious complications which the
greater flow of blood produces in such cases.
Till the present day no one knows what parts of the brain are consumed
in order to produce thought; no one can imagine how the molecules of
the blood penetrate the mass of cerebral cells and become part of
consciousness, and neither do we know how, from the joint life of the
single cells, something can arise which represents consciousness and
sensitivity.
Doctrines are here of no use. When our mind has arrived at the last
division of matter, at the last localisation of psychic processes, we
feel that it is vain to say we are materialists or spiritualists. All
schools are confounded in the nullity of our ignorance. The nature of
matter is as incomprehensible as that of spirit. From Lucretius, who
gave thirty proofs to demonstrate the materiality of the soul, down to
modern materialists, not one step has been taken towards the discovery
of the nature of thought. As a matter of fact, many materialists throw
down one dogma and build another out of its ruins.
If we reject the hypothesis of the spiritualists, we must, with the
same severity, banish from the borders of experimental science those
who, in our time, wish to explain, by means of materialistic doctrines,
the mechanism generating thought. Anatomy and physiology, the knowledge
of structure and of cerebral functions, have scarcely lisped their
first words, and dense darkness reigns over the nature of nervous
processes, over the physical and chemical movements animating the
hidden parts where consciousness has its throne. Let us speak neither
of spirit nor of matter; let us candidly acknowledge our ignorance. We
trust to the future of science and persevere in the search after truth.