paratus of adjustment from which the eyes never fully recover. The constitutionally feeble are in much greater danger of such a disaster. The very robust usually have enduring eyes, which they may abuse with comparative impunity. What, therefore, constitutes overwork in any particular case depends upon the predisposing causes which are referred to in the introductory part of this article, and may be considered more fully in a future paper.

It is our design to allude to that scourge of literary people denominated improperly by the old writers "Morbid sensibility of the retina," now described under the title of

ASTHENOPIA,

with the hope of indicating when the line of safety is being passed, when the brakes are to be applied, or when the eyesight is henceforward to be economized. We believe that our sugges tions, carefully regarded, may preserve that which is more valuable than money, and may save a lifetime of repentance and restriction.

Asthenopia is derived from the Greek word onεvos, strength, and p, eyes. It is really a derangement of the adjusting power. It is called by the German writers "incapability of sustaining the accommodation of the eye to near objects." Perhaps the best definition is intolerance of use. The retina has probably no capacity for sensation other than that concerned in seeing. The disordered sensations are sufficiently like disease of the retina to excite alarm, still the difficulty is with the accessory. apparatus of vision wholly, and the retina seldom becomes involved without the most blameworthy and continued imprudence.

It is believed that this disease is more common in this country than in Europe. Certain it is that in our climate there is a tendency to nervous excitability. The native European transplanted here loses his flesh, and somewhat assimilates the Indian type. The florid Englishman, at least in a generation or two, loses his color and gets Americanized. This has been attributed to our brilliant atmosphere, our high, dry wind, and other causes. That it is true, is evidenced by our hurried manner, our restless disposition, and our passion for new adventures. This affection of the eye is essentially a nervous disorder, and

would be likely to be developed by all that tends to increase the excitability of the nervous system. There is no doubt but the tightness of our houses, the smallness of our sleeping rooms, the use of anthracite coal, the abuse of gas-light, the great variety of our edibles, the indigestion produced by our love of sweets, and the want of simplicity in our diet, all contribute to produce this result. The working part of our population are overworked, and very few learn to economize nerve power, or by timely relaxation to prevent exhaustion.

But what are the indications that the bounds of safety are being passed, that it is wise to relax exertion and economize eyesight? In our work before alluded to,* the following indications are given of an asthenopic condition: "After reading, writing, sewing, or the like, there is a confusion and obscurity spread over objects, or there is a feeling of fatigue in the eyes which interrupts exertion. For a space of time varying from a few minutes to several hours the patient sees with perfect distinctness and with entire comfort, until warned by the symptoms before mentioned to desist. After a short period of rest, the patient is in a condition to recommence his employment. If the use of the eyes for the inspection of near objects is persisted in, weariness of the eyes is apt to be more frequent and of longer duration; although many struggle on through a series of years without any increase or diminution of the disability."

We find this disease frequently among clerks, book-keepers, tailors, jewelers, engravers, printers, and seamstresses, as well as students, who seem to be its principal sufferers. Those who work by artificial light are most frequently sufferers from this form of disability. This arises from the defective chromatic constitution of the rays of artificial light, its greater heating power, the production of carbonic acid gas, as well as the unsteadiness of the light, and its concentratedness and inequality. Labor of the eyes in which the mind is concerned, conjoined with feebleness of the body, temporary or permanent, most frequently produces this form of disease.

INDICATIONS TO STOP.

If the use of the eye is persisted in after the before-mentioned symptoms appear, graver ones manifest themselves. The *"Sight and Hearing."

object requires to be brought nearer to the eyes; there is a strained sensation, a feeling of distension, increased heat after using them, and perhaps excessive lachrymation. In some cases headache follows the use of the eyes, and a sense of weight is experienced. Frequently the edges of the lids become thick and red, and the eye is "bloodshot." In a few cases objects are indistinct, and vertigo may temporarily appear. If black motes or sparks appear, if sparks of fire or flashes of light are manifest, or objects seem to be surrounded by a halo, it is time to stop. No man can afford to continue the employment of the eyes upon near objects. He may yet save his eyes. Absolute rest of the eyes and mind are requisite, or what will often do better, an entire change of employment. Students and others are frequently imposed upon by quacks, and suffer from unnecessary alarm, supposing that they are attacked by amaurosis, while their difficulty is entirely sympathetic. A deranged stomach, overwork, or some other remediable cause, will produce symptoms of the same character. The motes and specks and scintillations thus produced are very much like the appearances that indicate more serious diseases. If so, other symptoms appear, and the obscurity is CONSTANT and generally may be identified; otherwise it is changing and occasional. The second diagram will help to distinguish the counterfeit from the true. An intelligent patient has furnished the exact appearance from the commencement of his attack, when he was nearly blind, till recovery finally took place under protracted medical treatment. This was a well-marked case of amaurosis. Still, no two cases are alike, except in the general features. It is difficult to convey a perfect impression of these objects on paper, and more difficult still to engrave them. The illustration on the next page will serve as some guide to direct the inquirer in the subject. The attack occurred suddenly, on an afternoon in July, as indicated at No. 1. After medical treatment for one week it appeared as at No. appeared as at No. 3; August 10, as at No. 4; August 31, as at No. 5; December 28, as at No. 6, almost cured; January 1, its appearance as at No. 7 indicated very indiscreet over use at the desk; January 4, improved again as seen at No. 8; Nos. 9, 10, 11, and 12, were drawn at longer intervals, until at length the disease wholly disappeared.

2; August 3, it

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HOW TO ECONOMISE EYESIGHT.

Says an eminent writer:* "Supposing a patient could work one hour, but no longer, without producing disturbance of vision, he should then be directed to work for half an hour at a time, and to allow intervals of rest of a quarter of an hour each; he can thus work two thirds of his usual time, while his cure proceeds. . . . The period allowed for employment should be short of that in which affliction produces the disturbance of vision, and the time devoted for resting the eyes should never be less than a quarter of an hour. Supposing that the impaired vision occur within half an hour, or less, after the eyes have been employed at work, it is best for the patient to refrain from work altogether for a week or two, until the affection be mitigated.

It is now fully conceded by the best observers that protracted rest of the eye is not useful. It is better to employ it than not, if caution is observed. Frequent rest, bathing in cold water, and careful avoidance of all the causes of derangement of eyesight alluded to under the heads of "Bad habits" and "Adjustment of light," will often prove curative. Dr. Weller in his "Diätetik für gesunde und schwache Augen," says: "The most excellent recreation with which the weakened eye can be indulged, is to move about in the free air, and in regions which

* Tyrell.

command an extensive and pleasant view of the face of nature." "The clear air is itself a medicine to the organ, and the beautiful distant prospect, while it delights, regales, and strengthens the whole man." By giving the eyes timely rest, and guarding carefully the general health, the asthenopic may accomplish much eye labor. Rest is safer than nostrums, and very far better than medicines if it is judiciously employed. He who relies much upon eyesight has little hope for continued power of vision if he neglects the laws of health or the virtue of temperance. Eyesight may be economised as well as money, and ought surely to be if there is a limit to its power. Treat the body well and it will generally do the work that we expect it to do. That the eyes fail, is usually the fault of those who possess and control those organs. Habits of mind must. be regarded as well as habit of body. The exercise of the intellect is healthful in a high degree, but the mind works with natural organs that may become worn out in doing its bidding. The amount of waste in brain power depends in a measure upon the demands made upon it. Brain work is not unattended with danger if judgment is not exercised, and the demands for rest are unheeded. "The proverbial eccentricities and failings of genius may find some apology in the feeling of lassitude which often follows its most successful efforts, and which too often drives its possessor to stimulating excitement for relief. The eye, especially if nervously diseased, is the first to sympathize with the overworked brain."*

The worst time to employ the eyes is at night; the worst part of daylight is immediately on rising. Individual experience will best determine what part of the day is the best. The only guide to the student must be the sensations produced by the excessive use of eyesight. If the eye feel pained, tired, or uneasy, it is hazardous to continue. No work is so important as to justify a continuance, if it has produced the symptoms of uneasiness. Most cases of serious "asthenopia" are traceable to some particular excessive use, when the warning to desist from labor was unheeded from ignorance of the danger, or because on some former occasion no serious result followed persistence. Relapses are very common and are easily induced. If ever relieved, those who have suffered from this form of dis

* Dr. George A. Bethune, Bibliotheca Sacra, April, 1855.