_A FEW PHENOMENA CHARACTERISTIC OF FEAR_
I
The edifice of the human body may be compared by those studying its
chemical processes to a vast manufactory of which every corner and
every door bears the inscription, 'NO ADMITTANCE.’ The curiosity of the
public could not be greater; fain would they force an entrance, for all
know that the most marvellous things are fabricated therein--wonders
which no human hand, no industry, can produce.
The workmen in this factory are very small--marvellously
small--invisible to the naked eye, and so tightly pressed together
that they sometimes resemble the cells of a beehive, and have, on this
account, received the name of cells. Life proceeds entirely from these
workmen, whose confederation is so perfect that not one can be touched
without the others at once becoming aware of it.
The edifice is somewhat weak in parts, and here one might easily force
an entrance and make a wide breach; but this violence would avail us
little, for when we break into the building the machines stop, causing
such disorder and confusion that we are quite bewildered. We hear a
whirring and throbbing, the pipes burst, the fluids are spilt, the
pumps stop, the valves open--then all grows cold and still; and this is
the strike which we call death.
The history of the attempts made to discover the actual nature of the
activity of these workmen who keep the secret of life is one of the
most beautiful studies in science; in reading it, there comes over
us a feeling of admiration and gratitude towards those men who, in
all ages, have spent their whole life in investigations, accumulating
experience, sacrificing worldly goods and honours for one little gleam
of light, defying poverty and toil, making the hardest and most cruel
sacrifices for the sake of one forward step, of lifting but a little
the mysterious veil, sometimes only to stretch out a hand to help
others to walk over their body.
Thousands of volumes have been written about this struggle, and those
who only read an epitome of it in the treatises of physiological
chemistry are yet astonished at the power of the human mind, and at the
incredible, almost superhuman, difficulties with which it has to cope.
Never was there, nor will there be, any war even faintly resembling in
ardour, perseverance, and power of intellectual means, this siege of
centuries, which seeks to close every issue to Nature and force her to
reveal the secret of her chemical operations.
It is wonderful to see how attacks are prepared in advance, what
cunning traps are laid, and by what subtile signs the road of ingress
is divined. Who can describe the joy of all besiegers when one step
forward has been made, or a glimmer of light is detected in the
darkness? The exultation and applause which welcome every invention
which resolves, or analyses, or recomposes a molecule, every instrument
which enables us to break one crumb off the immense rock of the
Unknown? And who shall tell the tale of pain, of disappointment,
bitterness, and error; of the forgotten or unknown deeds of heroism, of
existences lost in the obscurity of the schools, of the laboratories,
of the hospitals; of those who die unnoticed in these last trenches
where spectators and witnesses to shout applause are lacking?
And yet this deters no one; all press onward. The soldiers of science
renew their vigilance and redouble their caution, the phalanx of the
living draws closer together, returning with fresh courage to the
assault.
Nothing can resist this unremitting war, this wonderful harmony of
aim, this iron will of man; we will die on the battle-field with the
certainty that others will take up our weapons and that the victory
will be ours.
II
The prohibition to enter the manufactory of the human body is not so
strict but that we may advance a little. We can see everything which
goes in, that is, certain substances called food, which we all know,
because they are publicly offered for sale; nor is it difficult to
obtain permission to follow them through the mouth which forms the
entry, and a long corridor, called the œsophagus, into a large, damp,
warm cavity called the stomach, in which all substances are reduced to
a very fine pulp; the whitish juice runs into certain little canals
which flow into the circulating stream called blood, of which we have
already spoken, and out of which every workman, every cell, draws what
is necessary for its work. But no one has ever really discovered what
is done with this appropriated material--the manner of its digestion
and elaboration.
We know that the motor force of the manufactory is due to a change--a
chemical operation, by which the energy of the substances introduced is
transformed and appropriated by the cells that manifest it externally
in that force which we call muscular contraction cerebral activity, &c.
The most important chemical operations performed in the manufactory
are three in number. The first consists in the transformation of food
into protoplasm, or cell-substance; the second, in the discharge of the
energy accumulated in these cells; the third, in the elimination of
those substances which the cells have exhausted and rendered useless.
If we make a careful comparison, by means of chemical analysis, between
the composition of the substances introduced and those eliminated, we
always find that the chemical energy of the latter is much reduced,
from which we may know that it is food which puts everything in
movement, for with nothing, nothing is made.
The walls of the building are often moistened by a fluid which trickles
through in drops, and is called perspiration. Physiologists have
constructed most costly apparatus in order to collect the smoke of the
chimney and the air which escapes from the mouths of the innumerable
ventilators called pores. Every little thing was studied and
conscientiously analysed, and all were surprised that these elaborate
and most intricate operations of life should result finally in products
so simple. We may say that our body only produces carbonic acid, urea,
and a few salts.
III
Let us enter more fully into this subject, so that we may understand
the meaning of certain phenomena accompanying fear.
The materials rendered useless in the operations of our factory are
easily eliminated through the skin, which thus co-operates in one of
the most important functions, that of internal cleansing, which is more
particularly the office of the kidneys.
We have all observed that we usually perspire when the skin is red; but
there are exceptional cases, as in fear, when we perspire, although
we are pale and trembling. How does it happen that we have a cold
perspiration, and a perspiration with a sensation of warmth in the
skin? I shall here mention an experiment of Claude Bernard. Having
severed a filament of the sympathetic nerves on the neck of a horse,
he saw immediately afterwards, although the animal had not moved, an
abundant secretion on that half of its head where the cut had been
made. The mechanism producing this phenomenon is easily understood: as
soon as the nerve is severed which held the blood-vessels in check, the
latter dilate, blood flows more copiously to the sudoriparous glands,
increasing their activity and causing an elimination of the secreted
liquid.
When it is warm, or when we are feverish, and the blood tends to
flow more abundantly to the surface of the body to cool itself, the
secretion of perspiration is increased in a similar way. But we see
anæmic persons perspire--the consumptive, for instance, and the
dying, in whom this more copious supply of blood is wanting. In this
case the cause of abundant secretion is different; here it is the
nerves. One of the finest discoveries which have been made of late
years in physiology, is that of the nerve-filaments which connect the
cerebro-spinal system with the glands of the body. Whereas formerly
everything was attributed to the more or less copious flow of blood to
the glands, the secretions of which were considered as a process of
filtration, we now know that the matter is much more complicated, and
that there are nerves which augment and diminish the activity of the
cells charged with the secretion. It is nervous activity which produces
the perspiration characteristic of attention, pain, epilepsy, tetanus.
In order to prove that the secretion of perspiration may be
accomplished independently of the circulation of the blood, we make
an incision in the leg of a cat immediately after death and irritate
the sciatic nerve; we then see that a secretion of perspiration still
appears on the sole of the foot. From this we can understand how in the
death-agony and the extreme pallor of fright, when all the vessels of
the skin are contracted, there yet may appear a peculiar secretion of
perspiration which we call _cold perspiration_.
IV
There is another part of the body which opens periodically to allow of
the ejection of the refuse of the factory; it consists in a _cloaca_
and a cistern which contains a yellow liquid. It is a less beautiful
part of the organism, but during violent emotions involuntary movements
are produced in it so characteristic of fear that we must turn our
attention to it. Physicians thought that these irregularities were
caused by a paralysis of the sphincter muscle, but this is not the
case. The researches which I made with Prof. Pellicani[26] showed that,
in man as well as in animals, there are strong contractions of the
bladder which correspond to psychic facts. Scarcely have we experienced
some slight emotion or been excited by some thought but there is an
immediate change in the state of the muscles of this organ. I regret
that the nature of this book does not permit of the reproduction of the
curves traced by the plethysmograph, which show that psychic phenomena
and any irritation of the sensory nerves produce a contraction of the
bladder.
[26] Mosso e Pellicani: _Sulle funzioni della vescica_. R. Accademia
dei Lincei, vol. xii. 1881.
This is the reason why, during emotion, we feel the urgent and repeated
need to expel the urine, without the amount of accumulated liquid
being such as to explain the necessity. We can no doubt all remember
the annoyance which the contraction of this organ caused us on certain
solemn occasions; for instance, when we had to make a speech, or
present ourselves for an examination, or were anxiously expecting
something.
The feeling of contraction and pressure in the abdomen when we approach
a precipice, or when we are in great apprehension, is solely due to the
involuntary contraction of the bladder. We have shown that all causes
producing a contraction of the blood-vessels have the same effect on
the muscles of the bladder. I have often seen excitable, good-tempered
dogs, in whom caresses and the sight of food were sufficient to produce
such a contraction of the bladder, that the urine was expelled; and
this suffices to confirm the fact that in our organism the same
phenomena may be produced by opposite causes.
In emotions violently agitating the nervous system, and especially
in fear, the contraction of the bladder is so forcible that the will
can no longer hinder the expulsion of the accumulated liquid; it is
therefore not a paralysis, but too forcible a contraction of the walls
of the bladder which causes the involuntary expulsion.
* * * * *
Let us throw a passing glance at what takes place in the _cloaca
maxima_. The intestinal walls are as contractile as those of the
bladder; nor need this surprise us, as they are furnished with smooth
muscles, and receive nerves and blood-vessels from the same source.
We know, indeed, that this canal is subject to rapid movements, for
we have all frequently heard that rumbling noise of the intestines
which we cannot suppress. If the abdominal walls were transparent, we
should see, when this occurs, that there is a limited contraction of
the intestinal walls which propagates itself slowly in the direction of
the egress. These movements, called peristaltic, are present even when
we hear no noise; they serve to mix the food in the stomach, promote
digestion, and convey the useless residuum to the rectum.
In paroxysms of fear the rapidity of these movements is so greatly
increased that, in a very short time, they convey substances introduced
into the stomach to the terminal portion of the intestines before
there has been time to elaborate, digest, and condense them. It is
therefore no paralysis which may, in certain circumstances, make the
most courageous men appear ridiculous, it is a stream overflowing
its banks--the intestines contracting so violently as to eject their
contents rapidly from the organism.
One of my friends, who served as a volunteer in 1866, described to
me the physical disturbances which he suffered the first time he was
under fire. 'Believe me,’ he said, 'nothing can give you an idea of
the furious shower of bullets which whizzed about our ears. We were
near a cemetery; perhaps it was the sight of the crosses and of some
corpses lying by the road-side which increased my terror, but the
bullets burying themselves in the walls and trees, the cries of wounded
comrades, the grim rattle of musketry, the roar of the cannon, seemed
to tear me inwardly. The dysentery was so terrible that my body seemed
to fall to pieces. I was always cowering in the ditches, could only
stumble forwards, scarcely even rise from the ground. I was ashamed; I
could have killed myself only to be able to look death bravely in the
face, but, indeed, my organism could not bear that terrible sight!’
V
A still more characteristic phenomenon in the picture of fear is
_goose-skin_. Let us see how and why the skin corrugates in this way.
We know that besides the sudoriparous glands there are other glands at
the surface of the body which secrete a peculiar fat called _sebum_,
which oils the surface of the skin and gives it that gloss which we
notice on the face of some people.
If we take a vertical section of the skin, we can see with the
microscope a close network of muscular fibres which traverse the skin
in an oblique direction, and surround every hair in the manner of the
ribs of an umbrella. It is wonderful to see this mechanism under the
microscope, how every hair has its own gland, its own muscle and its
own nerve, its own arteries and veins. When these muscles contract,
the meshes of the skin contract likewise and express the contents of
the glands. We do not notice these movements of the skin, because the
muscles contract very slowly.
Sometimes special muscles appear in the skin called cutaneous muscles,
which play an important part in the life of animals.
We all know how the hedgehog rolls himself into a ball on the approach
of danger. This movement, as we have already stated, is executed by
means of a muscle covering the whole of the body, like a hood or
purse which may be drawn together on one side. In the mole, too,
these muscles are very strong, and we have already mentioned that
dogs and horses twitch the skin to rid themselves of flies, and that
this movement is due to a rapid contraction of one of these muscles.
When animals curl themselves up, with the muzzle close to the tail,
as the sleeping dog does, head and limbs are more easily held in this
position by means of these muscles. I have found them more or less in
all superior animals, and shall now consider the possible uses of these
muscles which exist also in man.
It does not seem to me correct to say that they serve to drive the
flies away, because they are well developed in reptiles and fish,
and in many animals of which the skin is insensible to the stings
of insects; also, if the fly-hypothesis were the correct one, the
cutaneous muscles should be best developed on those parts of the animal
which cannot easily be reached with the head, the leg, or the tail, but
the contrary is the case.
Certainly the muscles are made use of for this purpose, but this is an
accidental fact, as is also, I believe, the circumstance that these
muscles serve to erect the hair when the animal is excited or afraid.
When one dog approaches another in a hostile mood, there is such an
agitation of his nervous system that he begins to tremble, not through
fear, but excessive excitement. All the muscles contract, those of
the blood-vessels, of the bladder, of the intestines, therefore it is
comprehensible that the cutaneous muscles should also contract, raising
the hair on the dog’s back.
If we look at the skin of the arms or legs when we step into a cold
bath, or when we uncover ourselves on rising in the morning while the
temperature of the room is low, we notice the appearance of goose-skin.
Whenever there is, for some reason, a contraction of the blood-vessels,
these muscles contract also and the hair rises. The simultaneous
appearance of these two phenomena is, I believe, useful to the animal,
because, in raising the hair or feathers, the stratum of air enclosed
by these appendages is increased, the loss of heat in this way
diminished, and the cooling of the skin prevented. It is, perhaps, for
this reason that horses, dogs, cats, and birds ruffle their hair or
feathers when cold.[27]
[27] Darwin gives another explanation of this phenomenon which seems to
me less probable. He states that animals erect their dermal appendages
that they may appear larger and more terrible to their enemies.
But how can it be explained that these smooth muscles should be
originally dependent on the will? In order to avoid the doubly
improbable supposition that these muscles should have become smooth
and involuntary, although preserving the same functions, Darwin has
recourse to another explanation. 'We may admit,’ he says, 'that
originally the arrectores pili were slightly acted on in a direct
manner, under the influence of rage and terror, by the disturbance of
the nervous system.’ 'Animals have been repeatedly excited by rage and
terror through many generations; and consequently the direct effects
of the disturbed nervous system on the dermal appendages will almost
certainly have been increased through habit and through the tendency
of nerve-force to pass readily along accustomed channels.’ 'As soon
as with animals the power of erection has thus been strengthened or
increased, they must often have seen the hairs or feathers erected in
rival and enraged males, and the bulk of their bodies thus increased.
In this case it appears possible that they might have wished to make
themselves appear larger and more terrible to their enemies ...
such attitudes and utterances after a time becoming through habit
instinctive.’
'It is even possible ... that the will is able to influence in an
obscure manner the action of some unstriped or involuntary muscles, as
in the period of the peristaltic movements of the intestines, and in
the contraction of the bladder.’[28]
[28] Ch. Darwin: _The Expression of the Emotions_, p. 103.