Изображения страниц

thing, an egg-cup, or to a round wine-glass with a narrow stem. It is strong, so that it cannot easily be injured ; thick, so that light cannot pass through it; and round, so that it can be moved about in every direction, and let us see much better on all sides with a single pair of eyes than the spider can with its host of them.

In the front of the eye is a clear, transparent window, exactly like the glass of a watch. If you look at a face sideways, you see it projecting with a bent surface like a bow-window, and may observe its perfect transparency. The eyelids, which I have formerly spoken of as a curtain, may perhaps be better compared to a pair of outside shutters for this window, which are put up when we go to sleep, and taken down when we awake. But these shutters are not useless, or merely ornamental through the day. Every moment they are rising and falling, or, as we say, winking. We do this so unceasingly, that we forget that we do it at all ; but the object of this unconscious winking is a very important one. An outside window soon gets soiled and dirty, and a careful shopkeeper cleans his windows every morning. But our eyewindows must never have so much as a speck or spot upon them, and the winking eyelid is the busy apprentice who, not once a day, but all the day, keeps the living glass clean; so that after all we are little worse off than the fishes, who bathe their eyes and wash their faces every moment.

Behind this ever-clean window, and at some distance from it, bangs that beautiful circular curtain which forms the coloured part of the eye, and in the centre of which is the pupil. It is named the Iris, which is only another name for the Rainbow; for though we speak of eyes as simply blue, or gray, or black, because they have one prevailing tint, we cannot fail to notice that the ring of the eye is always variously mottled, and flecked or streaked with colours as the rainbow is. This rainbow-curtain, or iris, answers the same purpose which a Venetian blind does. Like it, it can be opened and closed at intervals; and like it, it never is closed altogether: but it is a far more wonderful piece of mechanism than a Venetian blind, and it opens and closes in a different way. There is nothing this iris so much resembles, both in shape and in mode of action, as that much-loved flower, the daisy. The name signifies literally Day's Eye; the flower which opens its eye to the day, or when the day dawns. Shakspeare, who saw all analogies, referring to the similar action of the marigold, in the morning song in Cymbeline tells how

“Winking Mary-buds begin

To ope their golden eyes." The daisy and the iris agree in this, that their opening and closing are determined by their exposure to light or darkness : but they differ in this, that the daisy opens widest when the sun is at its height, and shuts altogether when the sun goes down; whilst the iris opens widest in utter darkness, and closes so as to make the pupil a mere black point when sunshine falls upon it.

If we wish to observe this in our own eyes, we need only close them for a little while before a looking-glass, so that the dropped eyelids may shut out the day, when, like shy night-birds, the living circles will stretch outwards ; and the pupil of the eye, like a hole which the sun is melting in the ice, will quickly widen into a deep clear pool. If now we open our eyes, we see the rainbow-rings contract as the light falls upon them, and the dark pupil rapidly narrow, like the well-head of a spring almost sealed by the frost. But probably all have seen the movement I am describing, in the eyes of a cat, where the change is more conspicuous than in our own eyes; and have noticed the broad iris spread out in twilight, till the look, usually so suspicious, softened into a mild glance; whilst when Pussy is basking in the sun, as she dearly loves to do, she shows between her frequent winkings only a narrow slit for a pupil, like the chink of a shutter, or the space between the spars of a lattice-blind.

The endless motions of this living curtain, which, like the unresting sea, is ever changing its aspect, have for their object the regulation of the flow of light into the eye. When the permitted number of rays have passed through the guarded entrance, or pupil, they traverse certain crystal-like structures, which are now to be described.


(Continued.). Behind the iris is a lens, as opticians call it, or magnifying-glass. We are most familiar with this portion of the eye as it occurs in fishes, looking in the recently-caught creature like a small ball of glass, and changing into what resembles a ball of chalk, when the fish is boiled. This lens is enclosed in a transparent covering, which is so united at its edges to the walls of the eye that it stretches like a piece of crystal between them; and in front of it, filling the space dividing the lens from the watch-glass-like window, is a clear transparent liquid, like water, in which the iris floats. The lens is, further, set like the jewel-stone of a ring, in what looks, when seen detached, like a larger sphere of crystal; but which in reality is a translucent liquid contained in an equally translucent membrane: so that the greater part of the eye is occupied with fluid; and the chamber, after all, which it most resembles, is that of a diving-bell full of water. Lastly, all the back part of the eye has spread over its inside surface, first a thin white membrane, resembling cambric or tissue paper, and behind that a dark curtain; so that it resembles a room with black cloth hung next to the wall, and a white muslin curtain spread over the cloth. This curtain or Retina, seen alone, is like a flower-cup, such as that of a white lily, and like it ends in a stem, which anatomists name the optic nerve: the stem, in its turn, after passing through the black curtain, is planted in the brain, and is in living connection with it.

Altogether, then, our eye is a chamber shaped like a globe, having one large window provided with shutters outside, and with a self-adjusting blind within. Otherwise it is filled with a glassy liquid, and has two wall papers, or curtains, one white and the other black.

How small this eye-chamber is, we all know; but it is large enough. A single tent sufficed to lodge Napoleon; and Nelson guided the fleets of England from one little cabin. And so it is with the eye: it is set apart for the reception of one guest, whose name is Light, but also Legion; and as the privileged entrant counsels, the great arms and limbs of the body are set in motion.

Within our eyes, at every instant, a picture of the outer world is painted by the pencil of the Sun on the white curtain at the back of the eye; and when it has impressed us for a moment, the black curtain absorbs and blots out the picture, and the sun paints a new one, which in its turn is blotted out; and so the process proceeds all the day long. What a strange thing this is ! We speak of seeing things held before our eyes, as if the things themselves pressed in upon us, and thrust themselves into the presence of our spirits. But it is not so: you no more, any one of you, see my face at this moment, than you ever saw your own. You have looked betimes into a mirror, and seen a something beautiful or otherwise, which you have regarded as your face: yet it was but the reflection from a piece of glass you saw; and whether the glass dealt fairly with you or not, you cannot tell, but this is certain—your own face you never beheld. And as little do you see mine : some hundred portraits of me, no two the same, are at this moment hanging, one on the back wall of each of your eye-chambers. It is these portraits you see, not me. And I see none of you, but only certain likenesses, two for each of you, a right-eye portrait and a left-eye portrait, both very hasty and withal inaccurate sketches. And so it is with the whole visible world. It is far off from us when it seems nearest. Darkness abolishes it altogether. The mid-day sun but interprets it; and we know it not in the original, but only in translation.

Face to face we shall never meet this visible world, or gaze eye to eye upon it. We know only its picture, and cannot tell whether that is faithful or not; but it cannot be altogether faithless, and we must accept it, as we do the transmitted portraits of relatives we have never seen, or the sculptured heads of men who died ages before us. On those we gaze, not distrusting them, yet not altogether confiding in them; and we must treat the outward world in the same way.

What a strange interest thus attaches to that little darkened chamber of the eye! Into it the sun and the stars, the earth and the ocean, the glory and the terror of the universe, enter upon the wings of light, and demand audience of the soul. And from its mysterious abiding-place the soul comes forth, and in twilight they commune together. No one but He who made them can gaze upon the unveiled majesty of created things: we could not look upon them and live; and therefore it is that here we see all things “ through (or rather in) a glass darkly," and are permitted only to gaze upon their shadows in one small, dimly-lighted chamber. .....

The eye so triumphs over space, that it traverses in a moment the boundless ocean which stretches beyond our atmosphere, and takes home to itself stars which are millions of miles away; and so far is it from being fatigued by its fight, that, as the wise king said, “It is not satisfied with seeing.” Our only physical conception of limitless infinity is derived from the longing of the eye to see further than the furthest star.

And its empire over time is scarcely less bounded. The future it cannot pierce; but our eyes are never lifted to the midnight heavens without being visited by light which left the stars from which it comes untold centuries ago; and suns which had burned out, æons before Adam was created, are shown to us as the blazing orbs which they were in those immeasurably distant ages, by beams which have survived their source through all that time.

How far we can thus glance backwards along a ray of light, and literally gaze into the deepest recesses of time, we do not know; and as little can we tell how many ages will elapse after our sun's torch is quenched, before he shall be numbered among lost stars by dwellers in the sun most distant from us; yet assuredly it is through the eye that we acquire our most vivid conception of what eternity in the sense of unbeginning and unending time may mean.

It is most natural, then, that the eye, which can thus triumph over space and time, should hold the place of honour among the senses. Of all the miracles of healing which our Saviour per

« ПредыдущаяПродолжить »