« ForrigeFortsæt »
which is only known to us by the feelings which accompany it. Our idea of resistance, then, is the idea of our own feelings in applying muscular force. It is true, that the mere feeling of the muscles in action is not the only feeling concerned in the case. The muscles move in consequence of the Will; and what the Will is, we are not as yet prepared to explain. What is necessary at present is, not to shew all the simple feelings which enter into the feeling of resistance; but to shew that the simple feeling of muscular action is one of them.
The feeling of resistance admits of great varieties. The feeling of a plate of iron is one thing, the feeling of a blown bladder is another, the feeling of quick-silver is a third, the feeling of water a fourth, and so on. The feeling of weight, or attraction, is also a feeling of resistance.
SENSATIONS IN THE ALIMENTARY CANAL
WHEN the sensations in the alimentary canal become acutely painful, they are precise objects of attention to every body.
There is reason to believe that a perpetual train of sensations is going on in every part of it. The food stimulates the stomach. It undergoes important changes, and, mixed with some very stimulating ingredients, passes into the lower intestines; in every part of which it is still farther changed. The degree, and even the nature, of some of the changes, are different, according as the passage through the canal is slower, or quicker; they are different, according to the state of the organs, and according to the nature of the food.
Of the multitude of sensations, which must attend this process, very few become objects of attention; and, in time, an incapacity is generated, of making them objects of attention. They are not, however, as we shall afterwards perceive, feeble agents, or insignificant elements, in the trains of thought. They are of that class of feelings, to which we have already been under the necessity of alluding; a class, which serve as antecedents, to feelings more interesting than them
selves; and from which the attention is so instantaneously drawn, to the more interesting feelings by which they are succeeded, that we are as little sensible of their existence, as we often are of the sound of the clock, which may strike in the room beside us, and of course affect our ear in the usual manner, and yet leave no trace of the sensations behind.
The complicated sensations in the intestinal canal, like those in the muscles, though obscure, and even unknown, as individual sensations, often constitute a general state of feeling, which is sometimes exhilarating, and sometimes depressing. The effects of opium, and of inebriating liquors, in producing exhilaration, are well known; and though much of the pleasure in these states is owing to association, as we shall afterwards explain, yet the agreeable feelings in the stomach, are the origin and cause of the joyous associations. The state of feeling in the stomach in sea-sickness, or under the operation of an emetic, is, on the contrary, one of the most distressing within our experience; though we can neither call it a pain, nor have any more distinct conception of it, than as a state of general uneasiness.
The general effects of indigestion are well known. When the organs of digestion become disordered, and indigestion becomes habitual, a sense of wretchedness is the consequence; a general
state of feeling composed of a multitude of minor feelings, none of which individually can be made an object of attention.
In the sense of wretchedness, which accompanies indigestion, and which sometimes proceeds to the dreadful state of melancholy madness, it is difficult to say, how much is sensation, and how much association. One thing is certain; that sensations which are the origin of so much misery are of high importance to us; whether they, or the associations they introduce, are the principal ingredient in the afflicting state which they contribute to create.
The effects of indigestion in producing painful associations, is strikingly exemplified by the horrible dreams which it produces in sleep; not only in those whose organs are diseased; but in the most healthy state of the stomach, when it has received what, in ordinary language, is said, whether from quantity or quality, to have disagreed with it.
The general states of feeling composed of the multitude of obscure and unnoticed feelings in the alimentary canal, though most apt to be noticed when they are of the painful kind, are not less frequently of the pleasurable kind. That particular sorts of foods, as well as liquors, have an exhilarating effect, needs hardly to be stated. And it is only necessary to revive the recollection of