the work for which her training school fits her, and the great body of working nurses are content to stay in this field. Curiously enough, whenever we find a nurse straying beyond the imaginary line that now bounds her field on the north, south, east and west, we find some enterprising doctor either leading or driving her.

PUTTING A CHILD TO SLEEP.

All methods of putting children to sleep artificially by means of monotonous sensations are strongly censured, says the Healthy Home, including the crowing of lullabies and the rocking of babies in cradles or simply in the arms. Rocking the child in the arms or cradle is said to produce sleep partly because consciousness is fatigued by a series of monotonous sensations and partly because at the same time artificial anemia of the brain is provoked.

The approximate period of sleep necessary for children at different ages is given as follows: Between the ages of one and two years there should be from six to eight waking hours; between two and three years, seven to nine waking hours; between three and four years, eight to ten waking hours; between four and six years, twelve to fourteen waking hours; between nine and thirteen years, fourteen to sixteen waking hours.

There is much common sense in the foregoing remarks, but there is also a tendency to rather unduly press the point as to the harmfulness of oversleeping, particularly in the case of very young infants. Rocking a child in the cradle to any great extent is doubtless harmful, but it is difficult to understand in what manner the "crowing of lullabies" can affect the health of a baby. It is also no easy matter to fix the amount of sleep that a person-child or adult-should take by any hard and fast rule; a large degree of latitude must be allowed in this

TWO CONDITIONS WHICH INJURE

VISION.

N an article in the Buffalo Medical

IN

Journal, Dr. F. Park Lewis, the head of the American Association for the Conservation of Vision, discusses two conditions which injure vision. He says:

"The importance of human vision is so great that the loss of even a portion of the sight which might have been saved may so limit the usefulness of the person suffering such a loss as to change the whole course of his career. If, for instance, after an acute inflammatory condition of the eye, the patient emerges from the illness with but one-half of his normal vision, or if after the healing of a corneal ulcer absolutely normal vision for distance remains, but for the working range, by reason of the position of the corneal scars, is materially reduced, the general result would seem to be successful and the patient will have recovered, but the limitation of vision will throughout his whole future life prevent him from doing work which he might otherwise be qualified to do. It would limit. his studies, if it occurred in childhood; it would prevent his adoption of any mechanical trade requiring accurate vision, such as watchmaking, engraving or work of that kind. It would narrow his opportunities and circumscribe his possibilities in many ways.

have rendered such disastrous results far less common than they were a quarter of a century ago, and still they occur often enough to make us realize that the employment of conservative measures such as are designed by promptitude and efficiency to save human sight are important enough to receive consideration.

"I want, therefore, to emphasize some of those conditions in which the early recognization is imperative if sight is to be saved. One of the commonest of these which we meet is ophthalmia neonatorum. Possibly so much has been said about this during the last few years that it will be necessary only to refer to it. There are some facts connected with it, however, which may bear repetition and concerning which I may say a few words. We all know how infection occurs in the earlier cases, but we forget sometimes that there is such a thing as a late infection. Even the general public is now becoming familiar with the nature of the infection, the methods of its prevention and the necessity of its early and prompt treatment. Still, when I say to you that in so progressive a center as that of Boston, of 116 cases, 114 occurred in the practice of physicians and only two under the care of midwives, and of these 27 emerged with defective eyes and 9 were absolutely blind, we can not say that the time has gone by when every one knows what to do for ophthalmia neonatorum.

"If we are to control the disease of ophthalmia neonatorum, it must be by the concerted effort of the medical profession, the health authorities and the public. The following suggestions were made at the recent meeting of the American Medical Association to the Department of Hygiene and Sanitation with a view of standardizing methods of prevention which could be adopted in the

several States. There seems to be little doubt that within the next few years, if activities continue, it will cease to be the serious menace that it has always been to the eyes of the new-born.

"Blindness from birth infections has contributed one-fourth to the population of all the schools for the blind in the country. The existence of these infections is due to the failure on the part of the attendant, whether physician or midwife, to use the proper preventive treatment for the child's eyes during the first few minutes after it is born.

"Responsibility for this large amount of unnecessary blindness does not rest primarily upon the midwife and poor overworked doctor, but it does rest upon society, which means every intelligent individual who knows what should be done and whose influence should be used to aid in the protection of these helpless babies.

"The second condition which results with great frequency in lowered visual acuity is strabismus or squint. It formerly was not at all uncommon for physicians to advise the parents of a squinting child to wait until the boy was 16 or 17 years old before undertaking to have anything done for his relief. At six or seven years I have often found it impossible to restore the inturned eye to full visual acuteness. Nature is exceedingly unwilling that there should be useless functions. Strabismus is almost invariably due to the fact of there being two images in their nature like that obtained by a stereoscope. If the two sides of the human machine are mechanically different, it is impossible to force the two images to perfectly merge the one into the other. In the effort to accomplish this, the eye having the higher defect, or sometimes alternately, first one eye and then the other, will be drawn in. When the two eyes are almost but not quite in line double vision results. This is exceedingly uncomfortable. When the annoyance has persisted for a suffi

cient length of time, the eye which is turned in learns to suppress the image formed on that side. This is equivalent to saying that the visual center corresponding to the inturned eye has ceased to be active. When this dulling of a nerve center continues week after week, for several years, the nerves in that portion of the brain cease to develop and we have in the corresponding eye permanent amblyopia. If, on the other hand, by correcting the focal difficulties so as to make the two eyes functionate normally, making the visual centers equally active on both sides, or even if we have an alternation of the squint so that one eye sees equally with the other, although its fellow may be turned in, we perpetuate the visual function and sight is preserved.

"Whenever strabismus is found it should be placed under observation at the very earliest possible date. I have myself prescribed glasses for a squinting baby who is only five months old. In another instance, in that of an infant a year and thirteen days old, whose eyes 'converge badly, high hypermetropia was found in each eye, but differing in amount. The strong glasses which were necessary to make that baby see and to straighten its eyes and which were determined by means of the ophthalmoscope and the retinoscope not only straightened the baby's eyes but gave the little sufferer such comfort that two years later when the glasses had to be taken away in order to have the frames repaired he begged to have them given back to him, saying: 'I want my eyes.' That child will therefore have normal vision in each eye, fitting him for any work that may be undertaken. Had the use of glasses been postponed until the eyes could not functionate normally the inevitable operation might have restored parallelism, but it could not have restored vision, and a correction so obtained would in all probability be followed by a divergence later in life."

APPARENT ACCOMMODATION IN

APHAKIC.

Accommodation is defined by F. A. W. Kröner to be the power of the eye for retaining the same optimum of visual acuity at different distances. For practical purposes can be added-and showing this same optimum at a constant distance with different lenses before the eye, The visual acuity depends on the minimum separable. This power of the eye

The

depends for the greatest part on the adaption of the lens. Accommodation not dependent on this power we call "apparent." Kröner now investigates, if apparent accommodation truly exists, and wants to explain it, if present. His own investigations are preceded by a survey of the literature, some 125 publications. He examined 40 aphakic eyes. essential requirement is that the vision remains the same at different distances at which we examine. In all cases the corneal astigmatism, the form and size. of the pupil and of the opening of the secondary cataract, was measured; then the vision of each eye separately at six meters with Koster's optotypes. Generally the best correction with spherical glasses was first sought, then with simple or compound cylinders. The lenses were put in a frame with a constant distance between glass and eye. The vision was determined in the same way for 25 cm. distance, for which the same optotypes were used, but reduced by photography responding to distance. The head of the sitting patient was fixed, the optotypes put so that the visual plane had not to be lowered. This prevented narrowing of the palpebral fissure. As much as possible the line connecting the corneal apex with the optotypes was perpendicular to the center of the correcting lens. Only now and then the examination was done with artificial light; as a rule good daylight was used. Convergence was also prevented; closing of the palpebral fissure not allowed.

When accommodation was found, skiascopic examination was made with urg

ing to relaxation as well as to exertion, and the corneal curvature was measured with Javal's ophthalmometer. Other reflex images as those of the cornea were looked for in the dark room and with Tscherning's ophthalmophakometer.

Kröner found that in a certain number of cases of aphakia accommodation is present (in a little less than half the number of his cases). It is mostly small, about 1 D.; now and then higher up to 4 D. It appears more often at short distance than at 6 m. Inaccurate examination and wrong conclusions misled many in finding larger values.

It does not depend on a change in the relation of the refractive condition and the length of the eye. It was not proven on examination, and a number of facts were found contrary. It must be explained through the immutable relations of the aphakic eye, namely, through the regular and irregular astigmatism and the spherical aberration, which last one. also depends on the correcting lens.

The chromatic aberration, the imperfect centration, the diffraction, the opacities in the media, play a small rôle. Everything which diminishes the vision. favors the accommodation. The opening in the secondary cataract is mostly too large to have any influence. The difference in magnitude of the accommodation at 6 m. and at 25 cm. is chiefly explained with the stronger spherical aberration, dependent on the stronger correcting lens and the larger angle of incident of the light rays. The difference is still stronger at a distance of 10 cm. Smaller faults appear easier at shorter distance (25 cm.), not seeing exactly through the center of the lens, and the somewhat smaller pupil may have some influence; one is also more inclined for maximal exertion at nearer vision than at a distance.

The true refraction of the aphakic eye is not given by the strongest positive or weakest negative lens, which is chosen. for sight at 6 m. If the refraction was

exactly regular and the choice of the preferred lens only dependent on the influence of the pupil or opening of the secondary cataract on the size of the diffraction circles, then the intermediate lens would give the refraction. But as astigmatism, spherical aberration, etc., influence the indifference in the choice of the lens, we can not speak of just one refraction. The eye can not be corrected entirely with spherical and cylindrical lenses. Sometimes one lens will give the most favorable dispersive figure and this could be considered the refraction-determining one; often these figures differ too little with different lenses to produce a different vision. The distance of the cones to each other and their relative position in different directions will also have influence. This holds good also for the eye with lens, when its accommodation is paralyzed.

CORRECTION OF ERRORS OF RE-
FRACTION FOR MICROSCOPIC
WORK.

W. B. Leishman, in the British Medical Journal, points out that the eye-strain which not infrequently results from prolonged use of the microscope, especially when working with high powers and artificial light, is often so great as to cause considerable discomfort and headache, and may even lead to the abandonment of microscopic work, except for brief examinations. In many cases this trouble is caused by errors of refraction, more particularly by some degree of astigmatism. If this astigmatism is considerable, the microscopist is practically certain, in these days, to be aware of it and to possess glasses which correct his particular error, but if it is small it may never be detected until advancing years lead him to consult an oculist as to his first pair of presbyopic glasses. In either case, when he attempts to work at his microscope with spectacles or pince-nex in situ, he is certain to find them so uncomfortable and inconvenient that, sooner or later, he discards them and

trusts once more to his unaided vision and his powers of accommodation, with the frequent result that continuous work becomes increasingly difficult and the effects of eye-strain more conspicuous.

A small device has been designed with a view to correcting the error of refraction without employing spectacles. It is so obvious and simple that it is very probable that something similar may have been described and used long ere this, but, since the writer has been unable to discover that this is the case, it appears worth while, for the sake of others similarly situated, to describe the ocular cap which he has made for his own use. The increased definition which has resulted from the use of this cap is unmistakable, and there has also been a marked lessening of the feeling of strain which used to result from long hours of highpower work.

No lengthy description is needed, the principle being merely that the lens. necessary to correct the error of refraction of the eye commonly used is fitted accurately into the center of an aluminum carrier, so constructed as to form a cap which may be placed over the microscope ocular. In the case of a lens with cylindrical correction for astigmatic error the principal meridian is permanently marked on the carrier by means of an arrow arranged to set vertically. As most workers employ oculars of the same maker, the external diameter of which is approximately the same, the cap may be made to fit them all by arranging to have the internal diameter adjusted to fit the largest ocular used.

CONCOMITANT SQUINT.

C. A. Worth, in Ophthalmology, states that the onset of squint is most frequent in the second and third year of life. Some fusion faculty is present and remains effective until particular strain, illness or school renders it insufficient in the face of ocular difficulties. That squint is determined by motor difficulties