[10*] “Is there not reason to suspect, that our unconsciousness, in health, of the Impressions made on our organs by the fluids which they contain, depends on our being accustomed to the sensations which they incessantly excite; so that there remains but a confused perception which in time disappears.”—Elements of Physiology, by A. Richerand, translated by James Copeland, M.D., 4th ed., p. 21.—(Author’s Note.)
We are rather more attentive, perhaps, to the general states produced by the extensive diffusion of pleasurable or painful sensations in the alimentary canal, than in the channels of the blood, and perhaps we sometimes confound them. To some of the feelings in the upper part of the canal we attend sufficiently to distinguish them; the feeling called nausea, for example, in its numerous modifications. To those in the other parts, unless they amount to acute pain, we never attend, till they are so extensively diffused, as to constitute a state, to which we assign the terms, Comfort, Discomfort, or some other 336 of the vague names, by which a state made up of an indefinite number of painful or pleasurable sensations is usually denominated. Yet we know that actions of great importance are the result of those unnoticed sensations; the secretion of the gastric juice; the secretion of the bile; the separation of the nutritive from the innutritive part of the food; the operation of the lacteal and lymphatic vessels, and that extraordinary motion called the peristaltic, which aids in carrying on the contents of the bowels to the place of their discharge. It is probable, that the pleasurable states of the alimentary canal are commonly joined, or synchronous, with pleasurable states of the channels of the blood; and the painful states, the same. That the healthy, or unhealthy state of the one, accompanies that of the other, we know. And that certain diseased states of the circulating system, are accompanied with that general state of feeling, called discomfort, or wretchedness, which implies the wide diffusion of painful sensations throughout the system, is but too well known to all who have experienced any modification of the febrile state; nor can it be doubted, that the joyous state of perfect health, in which we feel delight in our being, and our whole frame seems to be a source of pleasure to us, is in a great degree produced by the innumerable unnoticed and unnoticeable sensations, produced by the motion and contact of the blood, in every part of our frame.
We seem authorized, therefore, by the fullest Evidence, to assume that Sensation, is the mental cause, whatever the physical links, of a great proportion of the muscular contractions of our frame; and that 337 among those so produced are found some of the most constant, the most remarkable, and the most important, of that grand class of corporeal phenomena.
2. To prove that Ideas, as well as Sensations, are the cause of muscular actions, it is necessary to make choice of cases, in which the Idea is in no danger of being confounded with that state of mind called the Will. And hardly any case will answer this condition, except some of those which are held to be involuntary, for the Idea itself never can be very clearly distinguished from the Will.
The Winking of the Eyelids, when a person moves his hand rapidly close to the eyes of another person, is a familiar case of an action of the muscles, which we cannot prevent. The idea is that of pain, from the contact of the hand with the eye. A sudden sensation of pain in the eye makes the eyelid close. This is the case, already examined, of contraction by sensation. When this has been performed, a number of times, the idea of pain in the eye, and the idea of the contraction of the muscles, that is, of the sensations contained in the contraction of the muscles, become associated together, so strongly, that the one can never exist without the other. The next step of the process is, that the contraction follows upon the Idea, in the same manner as it followed upon the sensation. This is not a matter of conjecture, it is matter of fact. It is an experienced event. We do not undertake to say, what physical links are between the Idea and the contraction, any more than between the sensation and the contraction. The Idea is the last part of the mental operation. And as the Idea and the sensation are feelings so nearly alike, there is 338 no difficulty in believing that like effects proceed from like causes.[60]
[60] The act of winking or wincing under the threat of a blow on the eyes is a good example of strong, and even indissoluble association. Any one making the experiment with an infant will find that there is no original tendency to perform the act. It is an association generated under the impressiveness of an acute pain, mingled with terror; a state of things under which an indelible mental connexion will be established in a very small number of repetitions. As a dog that has once suffered from a burnt cinder will dread for ever any commotion or stirring of the fire, so one smart in the eye will be associated with the cause in an indissoluble bond; and the mere sight of anything in motion towards the face will induce the preventive volition.—B.
The origin of the sensation, and the origin of the Idea seem to be different. The sensation originates in the extremity of the nerves at some particular part of the body. Something, we know not what, happens at the extremity of those nerves; something, we know not what, is conveyed along the nerves to the brain; and then sensation exists. From the brain, in its state of sensation, something, we know not what, is conveyed along the nerves to the contracting muscle, and the contraction takes place. Also, from the Brain, in its state of Ideation, if I may here, for the sake of the analogy with sensation, use a word of my own coining, something is conveyed along the nerves to the contracting muscle, and the contraction takes place. The sensation does not originate in the Brain; the Idea does. But if the state of the Brain when it has a sensation, and when it has the idea of that sensation, be, as we may 339 naturally suppose, very nearly the same; and if the state of the Brain is a necessary link in the chain of antecedents and consequents which terminates in the contracted muscle, the effect is so far accounted for.
Yawning is a familiar case of contraction, produced by sensation. We yawn without intending it; we know that we yawn in consequence of an antecedent state of feeling, of which, from never attending to it particularly, we have no distinct Idea; but which we recognise sufficiently as the antecedent of the act. This act, however, we also know is frequently the effect of Ideas. If we see another person yawn, it rarely happens that we do not yawn along with him. The act of yawning is so strongly associated with the idea of the feelings which precede it, that the sight of the act by another person calls up in us strongly the idea of the precedent feelings. The Idea exists, and as the contraction was the effect of the sensation, so is it also of the Idea.
The same is the account to be rendered of the infectious power of convulsions. In assemblies of men and women, especially under such a state of excitement (religious enthusiasm, for instance) as implies the strong association of certain trains of Ideas, if one person is attacked with convulsions, it commonly happens that others are attacked, and frequently great numbers. That this is a case of Ideas is certain; because nothing is conveyed to the spectators from a person convulsed, but the sight of the person; and the sight can do nothing but excite associated Ideas. The associated Ideas exist: the convulsions follow.
Laughter is a curious phenomenon of human nature. The analysis of it is not here required. It 340 will be easily recognised as a remarkable instance of the production of muscular action by Ideas. We laugh, either when certain ideas are suggested to us by others, or when they proceed from our own associations. In either case, the Ideas exist; the Laughter follows.