Physiological Researches on Life and Death

by Xavier Bichat

And to shew that they are gradually worn away by habit as we have said, to the point of indifference, a variety of proofs may be adduced. Every foreign body in contact for the first time, with a mucous membrane, is creative of a disagreeable sensation, which by repetition, is diminished, and at last becomes altogether imperceptible. Pessaries in the vagina, tents in the rectum, the canula made use of for tying polypi of the nose, or the uterus, bougies, in the urethra, in the œsophagus, or trachea, styles and setons in the lachrymal passages, present us every day with these phenomena. The impressions of which the cutaneous organ is the seat, are all of them subjected to the same law. The sudden passage from cold to heat, or from heat to cold, is always the occasion of a disagreeable sensation, but such sensation gradually and at last entirely disappears, if the temperature of the atmosphere be within a certain range and constant. From hence proceed those various sensations, which we have from the change of climate, or season. Similar phenomena in the same way are the result of our successive perceptions of the dry or humid, the soft, or the hard qualities of bodies, and in general the same may be said of all our relative sensations, of what kind soever.

With respect to pleasure, we shall repeat what we have said of pain. The perfumer and the cook are by no means sensible in their several professions of those pungent enjoyments of which they are dispensers. In them the habit of perceiving has blunted the sentiment. The same is the case with all agreeable sensations whatever. Delightful views and delicious music are productive of a pleasure, the vivacity of which is soon lessened; for harmony and beauty if they for a long time continue to solicit our attention, are successively the sources of pleasure, of indifference, of satiety, nay even of disgust and aversion. This remark has been felt by all; Philosophers and Poets have all of them turned it to their account.

From whence arises this facility, which our sensations have of undergoing so many different, so many contrary modifications? To conceive it, let us first remark that the centre of these revolutions of pleasure, of pain, and of indifference, is by no means seated in the organs, which receive or transmit the sensation, but in the soul. The affections of the eye, of the tongue, and the ear, are at all times the same from the same objects, but to these affections at different times, we attach a variety of sentiments. In the second place we shall observe, that the action of the mind in each several sentiment of pain or pleasure, which has been the effect of a sensation, consists in a comparison between this sensation, and that by which it has been preceded, a comparison, which is not the result of reflection, but the involuntary effect of the first impression of the object. Now, the greater the difference between the actual and the past impression, the livelier will be the sentiment. The sensations which affect us the most, are those which we never before have experienced.

The consequence is, that in proportion as the same sensations are repeated, the less impression do they make upon us, because the comparison between the present and the past becomes less sensible. Pain then and pleasure naturally tend to their own annihilation. The art of prolonging our enjoyments, consists in varying their causes. Indeed were I to regard the laws of our material organization only, I might almost say, that constancy is but one of the happy dreams of the poet, and that the sex to which we at present bend, would possess but a very weak hold upon our attentions were their charms too uniform; I might almost assert that were every female cast in the same mould, such mould would be the tomb of love. But here let us forbear to insist upon the principles of physiology, where they tend to the destruction of those of morality. The one, and the other are equally solid, though sometimes at variance. We shall only notice, that at times the former unhappily are our only guides. It is then, that love disappears, with the pleasure which it has procured, and leaves us but disgust. It is then, that recollection too often carries us aside from our duties in rendering uniform that which we feel and that which we have felt, for such appears to be the essence of physical happiness, that past pleasure enfeebles the attraction of that which we enjoy.

The consequences are clear. Physical pleasure is nothing but a comparative sentiment; it ceases to exist when uniformity supervenes between the actual and past impression. By means of this uniformity habit must bring down pleasure to indifference: Such is the secret of the very great influence which it exercises over our enjoyments.

Such also is its mode of action on our pains. Time flies, it is said, and carries away sorrow; time is the true remedy of grief; and wherefore? The reason is, that the more sensations it accumulates upon that which has been painful, the more does it enfeeble the sentiment of comparison between what we are, and what we were. At last this sentiment becomes extinct. There are no eternal sorrows.

III. Habit improves the judgment.

I have just now proved that the sentiment is enfeebled by the effect of habit. It is as easy to demonstrate, that habit improves and enlarges the judgment.

When, for the first time, the eye wanders over an extensive country, or the ear is struck by a succession of harmonious proportions; when the taste, or the smell for the first time are affected by any very compound savour or scent, there arise from these sensations only confused and inexact ideas. We represent to ourselves the whole, its parts escape us. But let these sensations be repeated, and in proportion as they are so, will the judgment become precise and rigorous, and the knowledge of the object be perfected.

Let us for instance observe the man, who a stranger to theatrical amusement of every kind is introduced to the Opera. He will have but a very imperfect notion of it. The dancing, the music, the scenery, the actors, the splendor of the whole will be all confounded within his mind in a sort of delightful chaos. But let him be present at many representations, and whatever in this charming whole belongs to the several arts, will assume its separate place. He will have seized its detail, may form a judgment of it, and this he will do the more accurately in proportion to his opportunities of observation.