I.
The relation of different emotions to the internal functions is a subject yet in its infancy. Our knowledge of it is still in a vague and confused state. It is at the same point where the problem of the expression of the emotions was before Charles Bell and Darwin; i.e., we have before us a purely empiric set of observed facts without suggested explanation. No doubt it is well known that vaso-motor and respiratory disturbances vary according to the emotions, but the reasons for the differences between one case and another are often unknown and even unexplored. Although Lange has done much in this direction, we cannot congratulate ourselves on having a complete presentation of all the organic and functional manifestations which accompany the simple emotions, not to speak of the complex forms. Still less do we know, clearly and positively, why these and not other manifestations are produced. Thus Hack Tuke asserts it to be a matter of common observation that while the blush of shame begins in the cheeks and the ears, that of anger begins with the eyes, and that of love with the forehead. Supposing this fact to be firmly established, we should still have to find out why, in each case, that particular vascular region should be affected by preference. In short, the study of the external conditions of emotion remains at the present time fragmentary and descriptive.
The part played by the viscera in the emotions and passions is so evident that in all ages it has arrested the attention of mankind. On this point, for a period of several centuries, we find, on the one hand, a popular psychology,—which in all languages has become fixed in the form of metaphors,—full of errors and prejudices, but also of very sound observations; on the other hand, scientific attempts at explanation, varying with the physiology of the period, and expressed in terms of the current medical doctrine. During this long period we can distinguish two principal directions of thought: one tending to localise the passions exclusively in the viscera, especially the heart, the other to place them in the brain. Without distorting facts, we might find in these two tendencies the incomplete and unconscious form of the two reigning theories in affective psychology, the organic and the intellectualist.
It would be of no interest to retrace this long history, to remind the reader that Plato placed courage in the breast and the sensual appetites in the abdomen, that the School of Salerno attributed anger to the gall, joy to the spleen, love to the liver. The organic or visceral theory long had an overwhelming preponderance, and Bichat, at the beginning of the century (1800), did not hesitate to write, “The brain is not affected by the passions which have for their exclusive seat the organs of internal life—the liver, lungs, heart, spleen, etc.” From the seventeenth century downwards, the cerebral theory becomes more accentuated; with Gall and Charles Bell the heart is quite dispossessed, and, by way of reaction, the part played by the viscera was almost forgotten.
At the present day no one maintains that the heart or any other organ is the seat of an emotion in the sense of feeling it; the consciousness of the affective life only exists through the brain, in which the internal sensations coming from the viscera are represented as external sensations; it is an echo. The brain, says Hunter, knows perfectly well that the body has a liver and a stomach, or, as Carus expressed it, each organ has its psychische Signatur. The ideal would be to determine, by means of a complete and well-conducted elementary analysis, the part contributed by each internal organ and function to the constitution of a particular emotion. Nothing of this sort can be attempted: there exist, on this point, only scattered materials and conjectures supported chiefly by the phenomena of morbid states. We shall return to this later on. (See Part II.) Let us at this moment confine our attention to the two predominant organs—the brain, the centre of psychic life; the heart, the centre of vegetative life.
1. The brain is not merely the echo of internal sensations; it receives and reacts according to its disposition; it centralises, but while taking its own part in the concert; it puts its mark on the impressions it receives. Already (Chap. I., § 1) we have seen the theories propounded as to the “seat” or “centre” of pain or pleasure: bulb, protuberance, temporal lobe, occipital lobe, etc. Naturally, each author has extended his hypothesis to the emotions properly so called. However, the search for “emotional centres” appears still more chimerical. A particular emotion has no determinate centre, is not localised in a restricted area of the encephalon. Not only does neither observation nor experience indicate anything of the sort, but if we consider the complexity of any emotion whatever, we shall understand that it requires the activity of several cerebral and infra-cerebral centres: (1) the sensory centres of sight, hearing, smell, etc.; (2) the centres scattered through the motor zone and regulating the movements of different parts of the body; (3) and lastly, the centres corresponding to the phenomena of organic life. These constitute several stages: in the spinal cord, the respiratory centre, that which accelerates the movements of the heart, the genito-spinal, the vesico-spinal (it is well known that the bladder is as good an æsthesiometer as the iris), etc.; in the bulb, the respiratory and vaso-motor centres, and those of cardiac and thermic inhibition. As regards the cortical layer, there are many open questions as to the position of the vascular, thermic, trophic, glandular centres, of the organic movements which determine the contraction of the intestines, the bladder, the spleen, etc. This very incomplete and confused enumeration is sufficient for our purpose—viz., to show that we must speak, not of a centre, but of the synergic action of several centres, differently grouped according to the cases.[[80]]
It is well known that the vaso-motor nerves of the head, the upper limbs, the lower limbs, the viscera, are furnished in part by the nerve-reticulations of the sympathetic system, in part by the rachidian nerves issuing from different parts of the spinal cord. Now, an experiment of Claude Bernard’s, made as far back as 1852, shows that the section of the great sympathetic in the neck produces on the same side an expansion of the vessels, and an increase in the temperature, nutrition, muscular tonicity, and sensibility. On the contrary, galvanism applied to the same nerve produces constriction of the vessels and the contrary phenomena to the preceding. Féré points out that the manifestations of the first case are, in general, those of the sthenic emotions, as those of the second are of the asthenic emotions.[[81]]
Whatever we may think of this comparison, the incontestable and so often recorded characteristic of emotion—diffusion—shows us that it is everywhere; that, if we could see with our eyes the cerebral mechanism supporting it, we should be spectators of the co-ordinated work of the multiple centres; that, consequently, the hypothesis of a localisation, of a seat in the limited sense, is in no way justified.
2. It is needless to remind the reader that the majority of idioms make the heart the incarnation of affective life, and that the antithesis of reason and passion is, in current speech, that of the brain and the heart. This opinion is not entirely a prejudice, as contemporary physiologists have shown.
Why is the heart, an unconscious muscle, promoted to the position of an essential and central organ of the emotions and the passions? It is so in accordance with the well-known physiological law which makes us transfer our psychic states to the peripheral organ which communicates them to our consciousness. It feels the rebound of all the impulses which strike us; it reflects the most fugitive impressions; in the order of the sentiments, no manifestation takes place outside it, nothing escapes it; it vibrates incessantly, though in different manners.
Claude Bernard, and after him, Cyon, have undertaken to justify the popular expressions regarding the heart, to show that they are not mere metaphors, but the result of accurate observation, and that they can be translated into physiological language. I here summarise their principal remarks.
The heart, the centre of organic life, and the brain, the centre of animal life, the two culminating organs of the living machine, are in an incessant relation of action and reaction which shows itself in two principal states,—syncope and emotion; the first due to the momentary cessation of the cerebral functions through intermission in the arrival of the arterial blood; the second due to the transmission to the heart of a circulatory modification. There is always an initial impression which slightly arrests this organ (according to[according to] Claude Bernard), whence a passing paleness, then a reaction which the heart, by reason of its extreme sensibility, is the first to feel; for, as the brain is the most delicate of the organs of the animal life, the heart is the most sensitive of the vegetative vital organs.
When it is said that the heart is broken by grief, this expression corresponds to actual phenomena. The heart has been arrested by a sudden impression, whence, sometimes, syncope and nervous attacks. The heart’s being “big,” answers to a prolongation of the diastole, which causes a feeling of fulness and oppression in the præcordial region. The “palpitation” of the heart is not merely a poetic formula, but a physiological reality; the beats being rapid and without intensity. The facility with which the heart is emptied, the regularity of the circulation being kept up by slight pressure, corresponds to the “light” heart. Two hearts beat “in unison,” under the influence of the same impressions. In the “cold heart” the beats are slow and quiet, as if under the influence of cold; in the “warm” heart, the contrary is the case. When we tell a person that we love him “with all our heart,” this expression signifies, physiologically speaking, that his presence, or the recollection of him, awakens in us a nervous impression, which, transmitted to the heart by the pneumogastric nerve, causes in our heart a reaction of such a kind as to produce in the brain a sentiment or an emotion. In man, the brain, in order to express its feelings, is obliged to take the heart into its service.[[82]]
Let us further recall the well-known observations of Mosso, who was able directly to study the circulation of the blood in the brain in three patients, in whom the cranium had been destroyed by various accidents. He ascertained that the mere fact of looking attentively at one of his patients, the entrance of a stranger, or any other occurrence of slight importance, immediately quickened the cerebral pulse. In one, a woman, the height of the pulsations suddenly increased, without apparent cause; she had just perceived in the room a death’s-head, which somewhat frightened her. The same thing took place with another patient when he heard the clock strike twelve; this was because he did not feel able to say his noon prayers. I do not dwell on his researches by means of the plethysmograph, which have special relation to intellectual work.
It will therefore be understood how popular opinion has come to look upon the heart as the seat, or the generator, of emotions. This is the instinctive expression of a quite correct view: the supreme importance to the affective life of the visceral action summed up in a fundamental organ.