Frank. What can be the use of the eyelids shutting up and down so often?

Emily. I should think it was to wipe the eyes clear of any thing that may get into them-is it not, mamma?

Mamma. Yes, and also to rest them from the constant glare of light which would otherwise give us pain.

Jane. Is there any use in the eye-lashes?

Frank. I can guess what they are for-to shade the light are they not?

Mamma. Yes, and also to catch any particles of dust, which might otherwise enter the eye.

Emily. Then there are the eye-brows too; can they be of any use?

Mamma. Yes, they are placed above to prevent the moisture from the forehead, from getting into the eyes.

The eyes are taken care of indeed!

Jane.
Mamma.

But this is not all; there is a fluid which is always keeping them moist and clean.

Emily. But, mamma, you have not told us yet how we see. Is it with the colored part, or with that black spot in the middle?

Mamma. That black spot in the middle is nothing but a hole.

Emily. A hole, mamma?

Mamma. Yes, and through it the objects which you see are reflected on a nerve which is called the optic nerve, and from thence sensation is conveyed to the brain. You remember, I hope, what I told you about the nerves?

Frank. Yes! You said they were white threads or strings, sometimes flat and sometimes round,

which were all connected with the brain, or the spinal marrow, and that they were the things which made us feel.

Mamma. You are right. The optic nerve proceeds directly from the brain, and expands round the eye at the back of it. So you can easily understand why any injury done to your eye would cause you so much pain.

Frank. Yes, but I cannot think how such great things as I see, can come through such a little hole. Mamma. You do not see the things themselves, but merely the reflection of them.

Emily. Do not I see you, mamma ?

Mamma. No, only the reflection of any image, just as when you look in a mirror, you do not see yourself, but merely your face reflected in the glass. It would puzzle you if I were to say more on this matter, at present. I will therefore tell you further about the eye itself. The colored part you see, is called the Iris, and the hole in the middle of it the Pupil.

Emily. Is the pupil always of the same size ?

Mamma. This you may easily find out for yourself; look at your sister's eyes, now she is turned to the light, how do the pupils look ?

Emily. Very small indeed.

Mamma. Now go with her into a part of the room where she will be in the shade, and tell me whether they appear at all changed.

Emily. Oh, yes ! they are a great deal larger.

Mamma. This is because the iris has the power of contracting, that is of drawing closer the opening, through which the rays of light pass to the brain, whenever these are so vivid that they would cause

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pain. It always does so when the eye is in a healthy state, but in some diseases it loses this power. Do you observe that the eye is not flat but rounded in front? Emily. Yes, mamma, is it the same in all persons? Mamma. In all it is rounded, but not in all equally Those whose eyes project very much are near sighted; but the full explanation of the reason of this belongs to the science I told you of just now. Frank. Is the eye flat at the back?

So.

Mamma. No, it is a round ball, sunk in a deep socket, and is composed of several different substances called coats, and humours; each intended to answer some valuable end in enabling us to see distinctly and pleasantly the various objects by which we are surrounded.

Frank. I think, mamma, there seems to have been more care taken of the eye than of any other part of the body.

Mamma. Yes, because it is of such immense importance to us, and because, from its situation, it is so liable to be hurt. Do you remember in the scriptures any texts in which God speaks of the care he takes of his people, comparing it to the tenderness we feel for the eye?

Frank. Is there not one text, mamma, in Deuteronomy, will you tell me whereabouts it is?

Mamma. You will find it in one of the latter chapters; begin at the 30th, and look till you see it.

Emily. Oh, I have got it; it is in Deut. xxxii. 10. Mamma. Read the 9th verse also, which shows the connexion.

Emily. "For the Lord's portion is his people ; Jacob is the lot of his inheritance. He found him in a desert land, and in the waste howling wilderness ;

he led him about, he instructed him, he kept him as the apple of his eye."

Frank. Is there not a text in the Psalms too like it?

Mamma. Yes; and in one of the minor prophets; I should like you to find them both: that in the Psalms is somewhere before the twentieth.

Frank. Here it is, mamma, in Psalm xvii. 8, "Keep me as the apple of the eye, hide me under the shadow of thy wings."

Jane. Now let me look for the other, do tell me about where it is?

Mamma. It is in the second chapter of Zechariah. Jane. Oh, I have found it; it is in the eighth verse: "For thus saith the Lord of hosts; After the glory hath he sent me unto the nations which spoiled you; for he that toucheth you, toucheth the apple of his eye."

Mamma. Now, then, whenever you feel how careful you are in preserving your eye from harm, and how suddenly you shut down the lid whenever you see any thing coming that may give it pain, you will learn how tenderly God takes care of His people; how He is ever watching over them to do them good: "lest any hurt them," he says, "he keeps them night and day."

Frank. Then, mamma, the better we understand how the eye is made, the more we shall be able to see how good God is, and how kind to us.

Mamma. Yes; every thing which we learn of His wonderful works teaches us this lesson more plainly. Frank. When you said that the pupil was a hole and not a separate part of the eye, I did not know whether you meant that it was hollow all the way

and open at both ends, because, if I look at you, it seems to me as if there was no hole on the surface.

Mamma. You are right. The eye-ball is covered externally, with the exception of one sixth part, by a coat which is called the sclerotica, which is a dense, hard, fibrous membrane, and has its name from this circumstance, as sclerotica means hard. The part which covers the other sixth of the eye-ball is the cornea, which is firm and resisting in its structure like the sclerotica, and is fitted to protect the exposed anterior portion of the eye, while its perfect transparency allows the free passage of light into the interior of the globe, and first converges the rays of light. These two coats are so firmly united that they may be considered as one continued investment of the eye, and as forming a kind of case for lodging and protecting its more delicate and essential structures. There is another coat called the choroid, which is spread uniformly within the sclerotica, and reaches to the margin of the cornea, the inner surface of it is covered with a black varnish. The next part to be considered is the iris, which is of considerable importance, and is highly curious from its peculiar motion and its office of regulating the quantity of light admitted into the eye; it is so called from iris, a rainbow, because of the variety of its colours; this membrane presents itself behind the cornea and seems like a continuation of the choroid coat: the anterior surface is the part in which the colour of the eye resides, which you know varies so much in different persons—it is perforated in the middle, forming the pupil. The posterior surface is called the uvea, from the Latin word uva, an unripe grape; because in brute animals, which the ancients chiefly