_PALLOR AND BLUSHING_
I
Man has, on the average, four kilograms of blood, and this fluid flows
incessantly in a system of tubes, in the centre of which the heart
is situated. The arteries carrying the blood from the heart to the
surface divide into many branches, separate, extend, and visit all
parts of the body, feeding and irrigating them. When the ramifications
of the arteries become so small that the eye can no longer see them,
as, for instance, in the lips, the finger-tips, the cheeks, the ears,
or any part of the skin, they take the name of capillaries. This is
meant to indicate that these little arteries are as fine as a hair,
but in reality they are very much finer. These last closely connected
capillary nets give the skin its beautiful rosy colour. But however
much they diminish, dividing and subdividing _ad infinitum_, they still
form a system of canals, with walls and closed on all sides. There must
be a wound, a cut, or a contusion, before the blood oozes out of these
little vessels. Out of the capillaries the blood passes into larger
canals called veins. Several veins flowing into each other form a
bigger vein; in the same way as a brook is formed by springs, as the
brooks, running into each other, form a rivulet, and the rivulets, a
river; so the veins gradually receive the blood in larger streams,
until at last they carry it in the great trunk-veins to the heart,
which drives it again into the arteries.
The little canals in which the blood circulates are provided with
muscular fibre. These may relax and the calibre of the vessels is
increased, or they contract and the calibre is reduced. The pallor, so
characteristic of fear, arises from a contraction of the vessels; the
beautiful blush of modesty, most eloquent of all the revelations of
psychic facts, is nothing else but a dilatation of the blood-vessels.
These two opposite phenomena do not depend on the heart, since we know
that the heart beats more forcibly and rapidly during the emotion of
modesty as well as during fright. From the nerve-centres innumerable
filaments branch off which are distributed to all the ramifications
of the blood-vessels. These are the so-called vaso-motor nerves,
which, without our noticing it, act on the muscular fibre of the small
arteries and veins, increasing or diminishing the calibre of the little
canals in which the blood flows.
The effects of the passions are far more evident on the countenance,
with its blushing and sudden pallor, than elsewhere, because in no
other part of the body are the blood-vessels so sensitive as in the
face. There are two reasons for this, firstly, the nerve-centres act
more powerfully on these vessels; secondly, they are more delicate,
sooner growing tired, and relaxing at the slightest disturbance of
nutrition. Indeed, if we inhale the vapour of a substance which,
like that of nitrite of amyl, paralyses the blood-vessels, the face
immediately becomes of a vivid red, and anyone making this experiment
feels his face aflame in a few seconds. This is the simplest method
which we possess for artificially producing the external phenomena of
shame.
At different ages and in different persons considerable differences
are noticeable with regard to the greater or lesser facility with
which they blush or grow pale. I made a long series of investigations
in order to see at what degree of temperature the paralysis of the
blood-vessels of the hands appears when we dip them into hot water, and
at what degree, and after what lapse of time, the hands begin to redden
when we hold them in ice-water or in snow, the differences being found
to be very considerable.
An old lady does not blush under those moral emotions which used to
betray her feelings as a girl; and this, not because age has overcome
the timidity of youth, or because the hard struggles of life have
blunted her sensibility, but because the blood-vessels of the face
have, in course of time, become less yielding. On long walks taken in
the sun, one always notices that the faces of babies are redder than
those of bigger children, and these, in their turn, are more flushed
than those of their parents.
Even persons of the same age do not respond in the same way to the
internal or external stimuli which tend to dilate or contract the
blood-vessels. It is well-known that all girls do not blush equally at
a pleasantry directed to them.
One must not ascribe the difference solely to shyness or modesty, since
the blood-vessels of different persons respond in various ways. In a
very warm room all the young girls have not equally flushed cheeks, and
if we pay attention when, on leaving a company, we touch the hands of
a great number of people who have been together for several hours in
the same room, we may easily notice the very great difference in the
temperature of the hands. In such circumstances, to have warm or cold
hands only means to have expanded or contracted blood-vessels.
Besides this action of warmth or cold, which is, so to speak, local,
there is another central action much more important to us--that which
produces the pallor, or flush of emotion. The nerve-centres can, by
means of the vaso-motor nerves, greatly alter the circulation in the
various parts of the body, as we all know from the continual changes
which the colour of the skin undergoes.
It is not necessary to mention the studies made on animals; the
observations which can be made on man suffice to show how this nervous
mechanism works. I know several persons whose blood-vessels differ in
sensitiveness on the right and left side, and who, therefore, feel the
effects of emotion more intensely on one side of the body.
At balls, on excursions in the mountains, and walks in the sunshine,
the attentive observer will notice great differences in the colour
of the two sides of the face. One often becomes aware of this from
the perspiration, which is more abundant on one part of the forehead
than on the other. My sister, for instance, when dancing, has one
cheek very much flushed, the other less so. With her, it is the right
side of the body which possesses more sensitive blood-vessels, which
are, therefore, more easily tired by exertion, heat, or emotion;
consequently this half of the face becomes redder, and receives a
greater quantity of blood.
A few days ago we went for a walk together into the mountains. Looking
down from a certain point we saw in the valley the funeral of a child.
A girl carried the little corpse, covered with flowers, on her head.
The bells of the village were ringing the 'Gloria,’ the funeral train,
with the priest at the head, appeared and vanished from time to time
between the green trees; children ran behind, carrying candles and
scattering flowers. It was a splendid autumn evening.
We had seen that little cherub with its golden hair just a few days
before, healthy and beautiful, enjoying itself at play, and now it was
to be hidden for ever under the cypresses of the churchyard. It was
our maid who carried the little one on her head; as she had said to
us, 'I must take him to be buried, because I am his godmother.’
My sister told me that as she watched she felt a shiver, as though she
had goose-skin all down the right side of the body, from head to foot.
Generally, the excitability of the vaso-motor nerves is the same in
both halves of the body, and we all experience during strong emotions a
feeling of cold, due to the contraction of the vessels, and spreading
over the whole body, as though a cold sheet were being wrapped round
our limbs and pressed upon our heart; this giving us an impression
which one might call a mingling of several indefinite and varying
impressions, as of darkness, cold, and of a dull, deep noise. The
impression is generally more perceptible in the head and back, more
rarely in the legs. Sometimes these contractions of the vessels take
place without our knowing the cause; the popular superstition says
that death is loitering near. It is one of those contractions arising
spontaneously, like the involuntary, sudden starts to which we are
often subject in bed before falling asleep.
II
Until recently no one had thought of studying the circulation in hands
or feet, since even the most practised eye cannot with certainty
distinguish the minimum variations in the colour of the skin, and
because the thermometer applied to the surface of the body cannot
accurately measure it. It occurred to me that one might easily attain
this object by measuring the volume of the hand. I took a long,
narrow bottle, and broke out the bottom of it. Into it the hand and a
good part of the fore-arm must be introduced, and the bottle closed
hermetically with putty. In the neck of the bottle I fastened a
stopper, through which a long slender glass tube passed, and filled
bottle and glass tube with tepid water.
I thought if a greater quantity of blood flows into the hand, an amount
of water corresponding to the increased quantity of blood will be
forced out of the bottle, and, on the contrary, if the blood-vessels
contract and the hand becomes smaller, the water contained in the
slender tube which passes through the stopper will flow into the bottle.
The first experiment, which I made on my brother, convinced me at
once that I had discovered the right method, although at that time I
was very far from imagining that I should be able to raise my simple
apparatus to the dignity of a scientific method, and with it to add a
chapter to the treatises of physiology.
I shall not detain the reader with a description of the perfecting of
this instrument, to which I gave the name of plethysmograph, or meter
of changes of volume.
A few months after making the first experiments on my brother, I
returned to Leipzig to see the celebrated physiologist Ludwig, in
order to tell him that I had thought out a very simple instrument,
by means of which interesting circumstances in the circulation of
the blood in man might be noticed. I shall always remember with deep
emotion the satisfied look with which he examined the sketches which
I, with trembling hand, drew upon the paper in order to make myself
intelligible, his sincere pleasure, and the words with which he
encouraged me to complete my studies in his laboratory.
I went to work at once and constructed two apparatus, one for each
arm, with the intention of studying the circulation in two parts of
the body at the same time. The phenomenon which had most surprised
me in my first experiments in Italy was the great instability of the
blood-vessels of the hand, in consequence of which it changed in volume
under the slightest emotions in the most surprising manner, whether the
subject were awake or asleep. A few days after having installed myself
in the laboratory in Leipzig, I was making an experiment in a room near
that of the professor, my colleague, Professor Luigi Pagliani, helping
me in everything with the devotion of a friend.
Our first object was to establish the relation between respiration and
change of volume in the hands. While Professor Pagliani was standing
before the registering apparatus, with his arms in the glass cylinders
filled with water, Professor Ludwig walked into the room. Immediately
the two pens indicating the volume of the arms, descended, as though
a vertical line, ten centimetres in length, were drawn down this page.
It was the first time that I had seen such a considerable decrease in
the volume of the hand and fore-arm, produced by an apparently slight
emotion. Professor Ludwig himself was very much astonished, and, with
that affability which made him so beloved by his pupils, took a pen and
wrote on the paper at that point where the plethysmograph had marked
the disturbance in the circulation caused by his appearance, _Der Löwe
kommt_ ('Enter the lion’).
III
In order to show more clearly the perpetual changes of locality which
the blood undergoes, accumulating now in one, now in another part of
the body, I constructed a balance of such a size that the beam (made
of wood) was sufficiently long and broad to allow of a man’s lying
at full length upon it, as may be seen in fig. 2. By means of the
weights, _R_, which run along the edge of the couch (moving upon the
fulcrum, _E_), it is easy, when the centre of gravity of the body is
nearly in the middle of the balance, to keep a man in equilibrium. In
order to prevent the balance swaying from side to side at every little
oscillation, I had to affix a heavy counterpoise of metal, _I_, which
can be moved up or down upon the screw, _G H_, fixed vertically in the
middle of the plank, _D C_, and firmly held by the lateral bars, _M L_.
[Illustration: FIG. 2. BALANCE FOR THE STUDY OF THE CIRCULATION OF THE
BLOOD IN MAN]
The centre of gravity of the balance is placed in this way so low down
that it no longer sways at every little oscillation, the counterpoise,
which moves inversely to the inclination of the balance, by its weight
drawing the plank with it, and bringing it again into a horizontal
position. I made the balance so sensitive that it oscillated according
to the rhythm of respiration.
If one speaks to a person while he is lying on the balance
horizontally, in equilibrium and perfectly quiet, it inclines
immediately towards the head. The legs become lighter and the head
heavier. This phenomenon is constant, whatever pains the subject may
take not to move, however he may endeavour not to alter his breathing,
to suspend it temporarily, not to speak, to do nothing which may
produce a more copious flow of blood to the brain.
It was always a pleasant sight to my colleagues, visiting me during
my researches, when they found some friend or acquaintance sleeping
on the balance. In the afternoon hours, which I preferred for my
investigations, it often happened that one of them would grow drowsy,
and be rocked to sleep by the uniform oscillation of this scientific
cradle. Scarcely had some one about to enter touched the handle of the
door, than the balance inclined towards the head, remaining immovable
in this position for five, six, and even ten minutes, according to the
disturbance produced in the sleep. Often, after waking, the blood was
no longer distributed in the same manner; the weight _R_ had to be
moved towards the feet, from which an amount of blood had retreated
in order to circulate more actively in the brain. The subject would
then gradually grow drowsy again, and the balance incline towards the
feet, the blood flowing, so to speak, from the centres of activity, and
collecting in the veins of the feet. The weight _R_ had now to be moved
in the opposite direction, until, in sound sleep, that distribution of
the blood took place which is peculiar to this state of our organism.
In the meantime the respiratory oscillations continued. Then, when
all was quiet, one of us would intentionally make a slight noise, by
coughing, scraping a foot on the ground, or moving a chair, and at
once the balance inclined again towards the head, remaining immovable
for four or five minutes, without the subject’s noticing anything or
awaking. And also, when all was silent in the still hours of night, or
during an afternoon sleep, one often noticed, without the appearance
of any external cause, oscillations, as it were spontaneous changes of
locality of the blood, arising from dreams or psychic conditions acting
on the vaso-motor nerves and modifying the circulation, without the
participation of consciousness, or at least without a trace of these
processes remaining in the memory.
IV
It was proved by my balance that, at the slightest emotion, the blood
rushes to the head. But this did not satisfy me. I wished to analyse
this phenomenon more minutely, and constructed other new instruments
in order to study it in all its particulars, and to follow the blood
while it streams from hands, feet, and arms to the brain. I have traced
the pulse for hours together, not of one part only, but nearly always
of several parts of the body at the same time--of the brain, the hands,
the feet, noting the slightest changes which the activity of thought,
external impressions, noises, or dreams produced on the blood-vessels,
waking or sleeping.
It was already known that the pulsations of the heart augment under
the influence of food and drink, but no one had observed, by means of
other instruments, certain modifications which the form of the pulse
undergoes, and which are so characteristic that I need now only see the
curve of a single pulsation of hand or foot in order to know whether
the person had eaten or was fasting. Again, between two pulsations
presented to me, I can distinguish that of the thinking and that of the
absent-minded man, that of the sleeper and that of one awake, that of
one who is warm and that of one who is cold, that of the tired man and
that of him who has rested, that of one who is afraid and that of one
who is tranquil.
One of my literary friends came one day to visit me in the laboratory,
in order to convince himself with his own eyes of these results, which
seemed to him scarcely credible. I proposed to make an experiment upon
himself, to see whether any change would be observable in his pulse
when he passed from reading an Italian book to a Greek one. At first
he laughed at the idea, but when we put it to the proof, we found
that with him also the pulse of the wrist changed considerably when
he passed from an easy work to the more difficult one of translating,
unprepared, a passage from Homer.
The vital processes are the more active the greater the rapidity with
which the blood circulates in our body; but in order to accelerate the
movement of the blood, the blood-vessels must contract. What we notice
in the course of rivers, namely, that the current becomes quicker
at that point where the bed is narrower, takes place also in our
circulatory system. When we are threatened by a danger, during fear,
emotion, when the organism must develop its strength, an automatic
contraction of the blood-vessels takes place, which renders the
movement of the blood more rapid in the nerve-centres.
It is on this account that the vessels at the surface of the body
contract, and we grow pale from fright or during violent emotion. I
have measured exactly the amount of blood which retreats from hands
and feet during the slightest emotions, also the number of seconds
between the moment when the emotion arises and that when the pallor is
greatest, but this is not the place for statistics.
A gentleman once told me that from fright a ring had one day fallen
from his finger which at other times he could only remove with
difficulty. He had also noticed that his fingers actually grew smaller
whenever he experienced strong emotion, thus rendering it easier to
take off the ring.
The proverb, 'Cold hand, warm heart,’ is the popular expression of the
fact that the hands grow cold when the blood, in consequence of an
emotion, retreats from the limbs to the heart.