attention, and to the image strengthened by repetitions, a preponderance which results in its revival.

IV. The same laws explain the opposite event; by suppressing or weakening the conditions which increase an image's chance of revival and preponderance, we suppress its chances of ascendancy and revival.-In the first place, all that lessens the attention lessens these chances. Every minute we experience twenty sensations, of heat, cold, pressure, contact, muscular contraction; slight sensations like these are being incessantly produced in all parts of our bodies; in addition to this, sounds, murmurings, and hummings, are constantly going on in our ears; a number of little sensations of smell and taste arise in our noses and throats; but we are otherwise engaged-we are thinking, meditating, talking, reading-and during all this time we neglect other things.

As regards other sensations, we are as if asleep or in a dream; the ascendancy of some dominant image or sensation keeps them in a nascent state. If, at the end of a minute, we attempt to recall them by memory, they do not revive; they are like seeds sown by the handful, but which have not grown; some single one, more lucky, has monopolized to itself all the room and nutriment the earth affords. It does not necessarily follow that these sensations, destined to obliteration, are feeble ones; they may be powerful ones: it is sufficient that they should be weaker than the privileged one. A musket-shot, the flash of a cannon, a painful wound, frequently escape attention in the heat of battle, and, not having been observed, cannot revive; a soldier suddenly finds he is bleeding, without being able to recollect the blow he has received.-In nine cases out of ten, and perhaps in ninety-nine out of a hundred, the sensation loses in this manner its power of revival, because there cannot be attention without distraction, and the predominance acquired by one impression is a predominance taken from the others. Here again, things are, as it were, in a balance; one scale can only rise by lowering the other, and the lowering or elevation of the one is in proportion to the elevation or lowering of the other.

On the other hand, the want of repetition also diminishes the chances of revival. Every one knows that we forget many of the words of a language when we have given up reading or speaking it for many years. So it is with an air we no longer sing, with a piece of verse we no longer recite, with a neighbourhood we have been long absent from. Breaks occur in the train of recollections, and go on increasing like the holes in an old garment. We have no difficulty in seeing how continuous and vast these destructions must be; every day we lose some of our recollections, threefourths of those of the preceding day, then others among those surviving from the previous month, so that before long a whole month, or even year, is only represented in our memory by certain prominent images, like those few peaks still appearing in a submerged continent, destined, at least the most of them, themselves to disappear, since the gradual obliteration is owing to a continuous flood, invading one by one the untouched crags, and sparing nothing but a few rocks uplifted by some extraordinary circumstance to a height no wave can reach. In fact, very few of our sensations, even of those accompanied by attention, are often repeated. Six months ago I was talking to such a person; after I left him, and even on the following day, I could have described his appearance and dress, have repeated the principal topics of conversation; but since then I have not renewed in experience or repeated in memory the images which then revived in me, intact and connectedly. They are obliterated, and now, when by chance I find some fragment of the distant scene, and stop to call up the rest, my efforts are vain. So it happens with nearly all the portions of our experience: the impression received has been a solitary one; in a thousand such, there is at most. one which is twice repeated; in a thousand of the repeated ones, there is scarcely one which is repeated twenty times. Some few only-those of permanent objects surrounding usof some twenty or thirty persons, pieces of furniture, monuments, streets, landscapes, derive from constant repetition a multiplied aptitude for revival. With the others, the aptitude

So

is too weak; when a fragment of distant experience, with
which they were formerly connected, reappears, they do not
reappear with it; the tendency which formerly called them
up is vanquished by other tendencies formed in the mean-
while; and the recent past blocks up the way of the earlier past.
Finally, on the other hand, images grow dull by repe-
tition, as bodies are worn away by friction. If we see a
person eight or ten times, the outline of his form and
expression of his face become at last much less clear in
our mind than on the day after we have first seen him.
it is with a monument, a street, a landscape, when seen many
times at different hours of the day, at evening, in the morning;
on a dull day, in rain, under a bright sun, if we compare
them with the same monument, landscape, or street, watched
for three minutes, and then replaced by some entirely diffe-
rent object. The impression, so precise at first, becomes less
so the second time. When I imagine the monument, I
find indeed the outline, which has remained constant all
the time, but the distribution of light and shade, the changing
nature of the tones, the look of the grey or blackened
pavement, the band of sky above-greyish and misty in the
one case, dark and tarnished in the other; sometimes a
bright white, sometimes a dark purple-in short, all the
diversities which at different moments have connected them-
selves with its permanent form, are mutually annulled. And
so, when I think of a person I know, my memory wavers be-
tween twenty different expressions, smiling, serious, unhappy,
the face bent on one side or the other. These different
expressions form obstacles to each other; my recollection is
far clearer when I have only seen him for a minute-when,
for instance, I have looked at his photograph or picture.

In fact, when the image of the form we have perceived tends to revive, it draws with it the images of its several accompaniments. But these accompaniments being different cannot revive together; the features of the same face cannot be at once smiling and severe; the façade of the same palace cannot be at once of an intense black, as when the sun is setting behind it, and of a rosy brightness, as when it is

rising in front of it. Therefore, if these mutually excluding accompaniments have an equal tendency to revive, neither one nor the other will do so, and we shall feel ourselves drawn in different directions by contrary tendencies which come to nothing; the images will remain in an inchoate state, and will make up what we call in ordinary language an impression. This impression may be strong without ceasing to be vague; beneath the incomplete image a dull agitation is going on, and as it were, a swarm of feeble impulses which usually sum themselves up in an expressive gesture, a metaphor, a visible summary. Such is our usual state as regards things we have many times experienced; a vague image, corresponding to a portion of our different experiences, a heap of contrary tendencies of nearly equal force, corresponding to their different circumstances, a clear notation, denoting and concentrating the whole in an idea.

A

This law of obliteration is of considerable extent, for it is applicable not only to different appearances of the same object, but also to different objects of the same class; and all the objects in nature may be grouped in classes. man who has passed through an alley of poplars, and wishes to figure to himself a poplar, or who, after seeing a large farmyard, wishes to figure to himself a hen, experiences a difficulty. His different recollections encroach upon each other; the differences which distinguished the two hundred poplars or the hundred and fifty hens are mutually obliterated; he will preserve a more precise image if he has only seen a single poplar standing in a meadow or a single hen roosting in a shed. All our images undergo a similar blunting; let the reader attempt to imagine a rabbit, a carp, a pike, a bull, a rose, a tulip, a birch tree, or any other object belonging indito a numerous class and of which he has seen many viduals, and on the other hand, an elephant, a hippopotamus, a magnolia, an American aloe, or any other object of a small class, and of which he has only met with one or two specimens; in the first case the image is vague and all its surroundings have disappeared; in the second it is precise, and one is able to point out the spot in the Jardin des

Plantes, the Parisian Conservatory, the Italian villa, where the object was seen.-The multiplication of experience is then a cause of obliteration, and images, by annulling one another, thus fall into the state of dull tendencies hindered by their contrariety and equality from assuming an ascendancy.

V. Thus we arrive at a general conception of the history of images, and, consequently, of ideas in a human mind. Every sensation, weak or strong, every experience, great or small, tends to revive by means of an internal image which repeats it, and is itself capable of repeating, even after long pauses, and this indefinitely. But as sensa

tions are numerous, and are at every moment replaced by others, without truce or termination, up to the end of life, there is a conflict of preponderance between these images, and, though all tend to revive, those alone do so, which have the prerogatives required by the laws of revival; all the others remain incomplete or null, according to the laws of obliteration. By force of this double law, groups of efficacious aptitudes are constantly becoming inefficacious, and images are falling from the state of actual to that of possible existence. Thus, human memory is like a vast reservoir, into which daily experience is continually pouring different streams. of tepid waters; these waters being lighter than the others rest on the surface and cover them; then growing cold in their turn, they descend to the bottom by portions and degrees, and it is the last flow that constitutes the new surface. Sometimes a particular stream, from being swollen or having a higher fall, warms ancient inert layers below, and then they remount to the light; the chance of the flow and the laws of equilibrium have warmed a certain layer so as to place it above the rest. The shape of the reservoir, the accidents of temperature, the various qualities of the water, sometimes even shocks of earthquake, all bear part in this; and many authentic instances show us deep layers uplifted suddenly and entire to the surface, sometimes superficial layers plunged suddenly and entire below.

In fact, images have, as we shall see later on, certain states of brain as conditions of their being; hence, we