CURIOUS LITTLE PAINTERS.
The next afternoon, when Catherine found her mother at leisure, she came and stood close by her, and looked in her face for some time.
“What are you looking at me for, so steadily?” said Mrs. Nelson.
“I am trying to see the pictures in your eyes, mother; and don’t you remember, that you said you would tell me more about these curious little painters, as you call them? Is it only that small dark spot in the middle of your eye that sees?”
“That little place, my dear, is a sort of window, which lets in the light that makes the picture upon the back part of the eye. It is called the pupil, and it is what is meant by ‘the apple,’ which you recollect being puzzled with in the Psalm that you read for your Sunday lesson. Do you remember it?” After a while, Catherine said, “Oh, yes;” and repeated this verse, “Keep me under the apple of thine eye, hide me under the shadow of thy wings.”
“By this little round window the light enters the eye, and passes through to the back part of it, and represents there, upon what is called the retina, everything that we see. So you perceive that if anything happens to the pupil of the eye, no light can enter it, and we should see nothing of all this beautiful and glorious world around us; we should be in perpetual darkness.”—“And now, mother, I understand the Psalm; for it is necessary that these two little windows should be kept very safe, as safe as we pray that God would keep us. But is that a little hole in the eye, mother?”
“No, my dear, this precious part of the eye has a covering over it like the chrystal of a watch; this is properly called the cornea, a Latin word that means like horn, because it resembles thin horn that the light can shine through,—as you may ascertain by asking the cook to show you a fish’s eye, and looking at this part.”
“And is the eye all hollow, mother? or what is between the pupil and the place on the back part of the eye where the picture is painted, that you called—I forget what you called it, mother?”