fatiguing for the accommodative power. Many a tedious case of weak sight has been traced to the pernicious habit of reading in bed after retiring for the night.

5. Do not read much during convalescence from illness. Before the muscular system generally has quite recovered its healthy tone, we ought not to expect the muscles of accommodation to bear the continuous use to which they are subjected in reading or writing. We cannot be sure that the delicate muscles of the eye are in a condition to be used until the muscles of the leg and the arm have regained their strength and firmness.

6. The general health should be maintained by a good diet, sufficient sleep, air, exercise, amusement, and a proper restriction of the hours of hard work. One ought not to expect strong eyes in a body weakened by bad habits or an injudicious amount of labour. Bright gas-lights in crowded rooms, and the impurity of the air in such places, are especially to be avoided. Medical advice should be sought in regard to any nervous debility, disorder of the organs of digestion, or any functional disturbances of a general nature, whether they appear to have a direct connection with the weakness of sight or not.

7. Take plenty of sleep. Sleep is a sovereign balm for those who suffer from weak sight. Retire

early and avoid the painful evening lights. Ten hours' sleep for delicate eyes is better than eight.

THE USE OF EYE-GLASSES IN WEAK SIGHT.

If the weak sight does not improve satisfactorily under the observance of the rules given, it will be necessary to resort to the use of convex glasses. It is better in this case to consult a competent oculist. He will furnish you a recipe, which may be taken to a good optician, who will sell you the glasses prescribed. The eye-glasses are to be used exactly as directed by the oculist. For the benefit of such as are unable to get proper advice, it may be well to say that the convex glasses will probably require to be of about 48-inch focus, and that they are to be worn only in reading, sewing, and such occupations as require the accommodative apparatus of the eye to be brought into use. The moment the eye tires, the glasses must be removed; to be replaced again, after a rest of the eyes, when work is resumed.

To accustom the eyes to the help of glasses may require some days or weeks and considerable patience. After beginning with them, it is best not to omit their use in reading or sewing, even temporarily, but to work or read always by their help; limiting the amount of reading at first, and

C

then increasing it day by day, or week by week, until the sight becomes strong.

WHY CONVEX GLASSES ARE USEFUL IN WEAK

SIGHT.

By looking at the figure below, you will see that parallel rays of light, or rays of light from a distance, are focussed exactly on the retina at the back of the eye (Fig. B). But divergent rays from near

objects, as seen in Fig. C, are not focussed properly. Next, you will observe that in Fig. D the rays of light are there again brought to a focus by means of the muscular adjusting power, or what we call the accommodative power. Notice in this figure that the lens (L) is more convex or full than in the other figures. This gives the eye a greater focal power; just exactly what it needs in looking at

fine objects quite near it. Now if we put convex glasses () before the eyes, it renders them practically more round and full, so that rays of light are focussed without calling upon the weak and fatigued

WHAT RESULTS IF NO ATTENTION IS PAID TO THE WEAK SIGHT.

If the symptoms of pain, confusion of vision, dread of light and of all use of the eyes continue, and no measures are taken to ameliorate or remove them, there is danger of the eyes not only becoming nearly useless, but that they may finally get so sensitive and irritable that ordinary daylight cannot be borne without pain and discomfort. When weak sight has been allowed to progress for years,

it sometimes becomes so severe that one finds a darkened room the only really comfortable place, dark-blue or smoke-coloured glasses not affording a sufficient protection from the light. I recall a patient several years ago, whose eyes had become so sensitive that he came to me wearing two pairs of glasses,-dark-green goggles and dark-brown spectacles, and these made it so dark that he could scarcely find his way about. I remember also his saying that if he raised his glasses at a street-crossing, to enable him to avoid passing vehicles, he would be obliged to spend two hours in a dark room to quiet the pain and discomfort. This was, of course, an exceptionally severe case. His eyesight was still preserved, but it was almost worse than useless to him.

Severe cases of weak sight are tedious and difficult to cure, and particularly so if of years' standing; but recent cases are curable.

OVER-SIGHT OR FAR-SIGHT.

This is a defect of a nature exactly the opposite of near-sight. In near-sight, the eye is adjusted or accommodated for a point nearer than the object looked at, and consequently does not see distant things distinctly. In over-sight, it is fixed for a point beyond the object looked at, and does not see well either near or far. In near-sight, the eye