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.

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.