Billeder på siden



at all points between opposing forces, we cannot relax every muscle of the body at once; the utmost we can do is to relax those that have borne the burden and heat of the day, and are the greatest in mass and energy; which necessitates the contraction of such as are opposed to them. I hold, therefore, that the tension of some members under pain does not invalidate, but rather confirms, the principle in question.

Another exception is the energetic expression prompted by acute pains. No one can say in the case of a man starting from a violent scald, that there is a relaxation of muscular energy; there is most manifestly the contrary. This seems a flat contradiction to our doctrine. In truth, however, this is the operation of another law of the constitution submerging at the moment the main principle, but only to make it emerge in still stronger relief. Sudden and acute pain is a stimulant of the motor nerves of the system. These become all alive for the instant, and throw a violent current into the moving members, inspiring a temporary spasmodic energy. Nothing could be more emphatically opposed to the doctrine here maintained than the appearance thus presented. But look at the other side of the picture. In the first place, this spasmodic burst has drawn away the regular supply of nerve force from the organic functions; all which will be found to be seriously impaired on the occasion; so that, at best, there is but a disturbance of the usually healthy direction of the vital power. And, in the next place, consider what happens at the end; how frightful the prostration that follows this painful stimulation. We shall then be convinced that, on the whole, power has been profusely sacrificed, although from the susceptibility of the nerves to an acute stimulus, there was for a time a manifestation of unusual energy.*

* In pain, the body is exerted to violent tension, and all the emotions and passions allied to pain, or having their origin and foundation in painful sensations, have this general distinction of character, that there is an ener getic action or tremor, the effect of universal and great excitement. It must at the same time be remembered, that all the passions of this class,

20. The consideration of the two great convulsive outbursts-Laughter and Sobbing-belongs to this part of the subject.

I shall say nothing at present as to the causes of laughter: enough that it is a joyful expression. The principal in the case is the Diaphragm, all else is subordinate and secondary. That large muscle, which is the principal agent in the act of inspiration, its contraction increasing the capacity of the chest, is convulsed in laughter; in other words, it is made to undergo a series of rapid and violent contractions. Some great accession of stimulus from the brain has reached it, and the consequence is that the person 'draws a full breath, and throws it out in interrupted, short, and audible cachinnations.' A charge of nervous power has been generated somewhere, and is here discharged into the great muscle of inspiration. The concurring or subsidiary actions also indicate an increase of power. When the laughter is audible, we know that the vocal chords have been made tense through a stimulus applied to the muscles of the larynx. The features also participate, and put on the expansive attitude at its fullest stretch. Whether, therefore, we look at the principal, or at the accessory, movements in laughter, they alike imply that new power has been evolved somewhere; and it is next to be seen, whether this is a real addition to the general vitality, or merely a transference from one part to another, impoverishing some organs, while violently stimulating others, as we have seen to be the case in the convulsions of pain. Now, except in excessive and immoderate laughter, or unusual depression of the system, it cannot be said that any vital function is starved, through the amount of force discharged in this violent manifestation. The testimony of mankind is in favour of the genial operation of laughter; but if digestion, perspiration, the exhalation from the lungs, or the action of the heart, were weakened to supply those con

some more immediately, others more indirectly, produce in the second stage exhaustion, debility, and loss of tone from over-exertion.'-Anatomy of Expression, p. 154.



vulsive movements of the diaphragm, we may be quite sure that the reaction would be unequivocally depressing, no less than that of acute pains. The proof is decisive that this outburst of joyful emotion is a sudden heightening of the powers of life, which more especially shows itself in increased and convulsive respiration, in vocal tension, and in the pleased expression of the features.

The convulsive outburst of grief contrasts strikingly with the above. The principal in the effect is still the convulsive action of the chest; but mark the difference. The expiration, which in the other was violently increased, is rendered slow. The diaphragm must answer for this fact, or rather the nervous centres that maintain it in operation. These centres, instead of overflowing, have become bankrupt; they cannot even keep up the usual supply of power. This partial stoppage, or paralysis, of the diaphragm is a key to the whole phenomenon. To prevent suffocation, the muscles of inspiration have to be stimulated by efforts, like the application of bellows to inflate the lungs of a drowning man; which forces. on, by reaction, an additional expiratory impulse. The great declension of vital energy is apparent. The accessories attest the same fact. The voice is feebly exerted, and the consequence is a long-drawn, melancholy note. The pharynx is convulsed, and is incapable of its rhythmical movements in swallowing. The features are relaxed, except in so far as they sympathize with the efforts of forced inspiration. These appearances are sometimes modified, as when a robust child bursts out in a violent fit of crying, expending a great deal of energy on the occasion. Great animal spirits can afford this manifestation; and it may be little else than an outlet for surplus power, having less of sorrow than of anger. But that would not be the fair or typical instance. In all cases, the reaction shows that power has been wasted and the system impoverished, the very opposite of laughter.

The lachrymal effusion is an accompaniment of grief, but there are also tears of joy. In the extreme of merriment, the eye is moistened and suffused. We can easily suppose, that

an increased vital stimulus of the lachrymal gland and sac would promote the secretion of the healthy liquid, and that this, by coursing over the sensitive surface of the eyelids, would give a certain genial sensation, which we enjoy in the happy moods of tender emotion. The amount may be increased so as almost to reach the point of visible drops, and still be of the genial character. But we must not conclude that the profuse stream that overflows in the outburst of grief, is merely the same action carried one stage farther. The common fact of abundance of liquid does not prove that all else is the same. As we may have a profuse salivation, containing very little of the material that avails for insalivating the food, so we may have a profuse lachrymal effusion, caused, not by the increased, but by the diminished action of the gland, in which case the quality would be radically changed. I make this assumption partly on speculative grounds, and partly because I think any one will recognize a difference in the sensation of the eyelids, when moistened under a joyful wave, and when the moistening comes of pain or depression.

Not only in painful states, but also in extreme instances of pleasurable emotion, the blood-vessels of the brain are congested, and the effusion of tears is one mode of relief.

21. The principle now contended for not only explains a large and important region of facts, but is essential to the preservation of the individual. If pleasure were something subversive of vital force, our system would be a house divided against itself. On the other hand, if the above principle were rigorously true, we should never be inwardly moved to act in a manner prejudicial to our physical welfare. That we are so moved is, then, a proof of the existence of some modifying influence, which must be brought to light, in order to complete the theory of pleasure and pain. It has been seen that the ordinary pleasures of the five senses do not point to any great or marked increase of vitality; and one might say the same of many of the special emotions-wonder, affection, power, knowledge, fine art, &c. That these are accompanied



by some increase of vital power is proved by their expression, which is of a lively, animated kind, whenever the pleasure is considerable. But it could not be said, that the increase of vigour in the system at large corresponds on all occasions to the degree of the pleasure. A still more startling exception is presented by the Narcotic stimulants, for these are known to debilitate and waste the powers of life. And if it be maintained that this is only an after consequence, and corresponds to the stage when the mental tone has changed to pain and depression, I reply that such is not strictly the fact; a man drinking to intoxication loses his physical energy before the feeling of exhilaration abates; and the pleasurable excitement of tobacco and of opium may continue under an almost total prostration of the vital forces.

We are thus called upon to qualify the doctrine that connects Pleasure and Self-conservation, by another doctrine connecting Pleasure simply with Stimulation. The precise limits of this second principle are to be determined by an. examination of the facts.

22. It is convenient to divide the modes of stimulation into two classes: First, what may be called the natural stimulants of the Senses and the Emotions; and secondly, Narcotics and Drugs.

First. On examining the natural stimulants of the Senses, what we appear to find is this. Touches, Sounds, Sights, are pleasurable within certain limits of intensity (excepting perhaps discordant sounds). Pain in these three higher senses arises from excess in the stimulus applied. The point of excess is exceedingly variable in different persons, and in the same person at different times; and notoriously depends upon the vigour of the system. So that we may say with certainty, as regards the sensations of Touch, Hearing, and Sight, that sensation, as such, is pleasurable within limits determined by the vigour of the nervous system. As regards the chemical senses, Taste and Smell, we cannot lay down the rule in the same positive manner; we cannot affirm the difference between painful tastes or odours and

« ForrigeFortsæt »