ing, as hot as could be comfortably borne; and after the eye was dried from the fomentation, a quantity of a tinctura opii mitis was dropped into it.

*

But sometimes, in very confirmed cases, it became requisite to apply a permanent blister to the head, below the ears, or between the shoulders.

Under this management modified to the peculiarities of individual cases, the disease usually subsided in a very short period; and due perseverance, with the addition of tonics, when the congestion was removed, effected permanent cures.

There are diseases of the eye so nearly resembling this as to be mistaken by very able men. It is essential to clearly ascer tain these, because the remedies proper for them will be useless in "weakness of sight," and vice versa.

"By the disease termed by Hippocrates, amblyosmos; by Aretæus, amblytes; by Etius, visus debilis; by Boerhaave, visus hebetudo; and by some French writers, vue confuse, faiblesse de la vuë, and mauvaise vue is not to be understood the same complaint which is described in this Dissertation, under the name of weakness of sight, but rather an indistinctness of vision, or absolute and complete ambliopy.t

This ocular complaint, properly called Dulness of sight, I must briefly

*The following formula is given for this tincture. R. opii purificati, croci anglica. āā žij. spir. gallic. alb. zj. aquæ distillata zvij. macera in vasc clauso per sex dies, deinde tincturam cola.

The patient being placed in a supine posture, with the head somewhat elevated, and the eyelids gently closed, a little of this tincture should be poured into the inner canthus of the eye, from whence it should be suffered gradually to insinuate itself between the palpebræ, by inclining the head to that side, and, at the same time twinkling the eye-lids; avoiding, in the interim, most carefully, every rude effort forcibly to separate them. It may be applied by means of a camel hair pencil, in the following manner. The operator, with the fingers of one hand, must cautiously depress the lower eye-lid, by which it will be somewhat averted (inverted), when the pencil, fully charged with the tincture and held in the other hand, is to be rapidly and dextrously swept across its inside, permitting the eye-lid instantly to resume its proper situation: p. 82. It seems an object to accurately diffuse the tincture over the whole anterior surface of the globe of the eye, and in particular to bring it in contact with the whole of the cornea. A rude application of this tincture, by forcibly pulling open the eye-lids, and dropping it upon. the centre of the cornea, increases the pain, and adds to the irritation.

+ Ambliopia est visûs debilitas sine admodum visibili oculi vitio. Myopes et presbytes in certá objecti distanciâ solummodo confusé vident: nyctalopes et hemeralopes certo diei tempore tantum inile vident, át ambliopes in quavis distanciâ et quôvis diçi tempore objecta debilitèr discernunt. Plenck Doesrina de Morbis Oculorum, Pa 186.

notice, because I have known it confounded with weakness of sight, although it is in fact the very reverse; and depends not upon an excess, but a positive want, of sensibility of the retina.

The principal symptoms are, not only frequent alterations in regard to the precise limits, but also a great indistinctness and confusion of vision; under all circumstances of time and place. If the eyes be much exerted, they soon become fatigued, which renders it necessary, every now and then, to close and gently rub them, when the patient can again see somewhat better for a short time. The eyes appear dull and inanimate. The iris, which is more or less dilated, is susceptible of very feeble, oftentimes scarcely any motion, even on the sudden impulse of a strong light, which occasions very little uneasiness. This malady is most apt to attack persons who are past their meridian; and is generally brought on by the too free use, or rather abuse, of the organ of vision, co-operating with other causes which have a tendency to debilitate the general and nervous system. The disease not unfrequently remains almost stationary for a great length of time. In other instances its progress is much more rapid, when it generally terminates in complete gutta serena, or total blindness.

*

Various and extremely contradictory remedies have been recommended by oculists for the cure of this very formidable complaint; which, however, I shall forbear at this time enumerating. The first thing to be attended to is, to allow the eye as much rest as possible, and to avoid particularly what may be considered the exciting causes of the disease. It is, I believe, in many cases absolutely incurable: and the only remedies which I have ever known to prove beneficial, are topical stimulants, as electricity, galvanism, æther, infusion of capsicum, rubefacients applied to the palpebræ, &c. whereas, in genuine weakness of sight, these means are certainly useless, some of them highly hazardous. Internally, too, mercurials given so as slightly to affect the mouth, together with the arnica montana, and deobstruent medicines, have sometimes been productive of benefit. Double convex glasses, by concentrating the rays of light, never fail to afford, in this case, considerable assistance to the sight.

It is this particular species of disease to which I presume Mr. Ware alludes in the following passage. "I cannot omit to mention," says he, (Vol. I. p. 122) that in some instances where the eye has been par ticularly weak," (a term he employs in a vague and indefinite manner), "without any perceptible cause to produce it, the application of spirituous remedies that have been highly rectified, such as the medicine sold at Riga, under the name of the Riga balsam, or the æther of the Lon

* I think it consonant with the present discussion to remark, that some cases which were deemed instances of gutta serena, I have ascertained to be examples of actual dulness of sight, and that they derived the most essential assistance from the application of the electric and galvanic influence. And I cannot forbear to add, that a few cases of blindness, which have fallen under my observation, and which were likewise ascribed to a paralytic state of the optic nerve, were altogether sympathetic affections, depending upon visceral irritation; by the removal of which the patient has obtained a complete cure. the latter description are the successful instances of amaurosis, related by Richter, Schmucker, and Scarpa.

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(No. 143.)

don

don pharmacopoeia, either alone or mixed with an equal proportion of sugar and water, has sometimes been greatly useful. In a few instances also, the excitement of a violent inflammation, by the application of other stimuli, has been found of use to overcome the enfeebled action of different parts of the eye."

Dulness of sight again differs from the Glaucoma, as there is not that deep-seated grey appearance, or shining pearl colour, observable in the latter complaint.

I am well aware, and have met with many examples of a slight species of Psorophthalmy, which, if only cursorily regarded, seems, in some respects nearly to resemble weakness of sight. Mr. Ware, indeed, appears, from the cases he has published, to have actually identified it with this complaint. I think it necessary, therefore, to dwell a little upon this topic; and I doubt not to be able to prove, by contrasting their respective symptoms, and the different modes of cure they indivi dually require, that they are in reality perfectly distinct ailments. The description of this affection of the ciliary glands is so accurately given by that respectable author, that I shall take the liberty of transcribing the particulars, and of subjoining a few remarks in support of my opi

nion.

"The psorophthalmy," says Mr. Ware, (Chirurgical Observations relative to the Eye, Vol I. p. 116), "not unfrequently occurs, without producing the slightest appearance of inflammation, either in the eye or eye-lid. I have attended a very considerable number of such cases; and in many, the only intimation of the nature of the complaint has been derived from the description given by the patients themselves. Whenever I am informed that the edges of the eye-lids have a disposition, be it ever so slight, to adhere to each other after they have been long in contact, as during the time of sleep, and when this is accompanied with an uncomfortable sense of weight in the lids on the approach of night, in consequence whereof the patient involuntarily shuts them without being drowsy, and without any particular stimulus being applied to the eye to give it pain, I always suspect that the secretion of the ciliary glands is in a diseased state; and in many such cases, I have found the suc cess attending the use of the unguentum hydrargyri nitrati, recommended for the cure of this disorder, quite as effectual as in those other instances, where the excoriation and redness of the eye-lids have been visible on the slightest inspection."

There are, however, several symptoms above mentioned, which deci. dedly characterize that species of diseased ciliary glands, and which serve at all times to distinguish it from the subject of this Dissertation. I allude to the uncomfortable sense of weight in the lids on the approach of night, the tendency of the tarsi to adhere together during sleep, and the involuntary disposition to shut them without being drowsy, and without any particular stimulus being applied to give them pain.

In the complaint in question, on the contrary, the meibomian glands perform their functions in the most perfect manner, consequently there is not any sense of weight of the palpebre towards the close of day, inducing a propensity to shut them independently of drowsiness or uneasiness, nor is there any adhesion of their edges during the night. Hence, the application of mercurials to the tarsi, which are almost specific in the psorophthalmy

porophthalmy are absolutely useless, often prejudicial in genuine weakness of sight. Besides which, the acute pain excited by the admission of a vivid light to the eyes in cases of the latter disease, furnishes a striking discriminating feature, sufficient to point out a decided difference between weakness of sight, and the above described slight species of psorophthalmy.

The injuries done to the delicate structure of the organ of vision by the improper treatment of many of its complaints, especially those of the minor class, by their falling to the care of empirics, and nostrum-mongers, or even under gentlemen regularly instructed, and sufficiently qualified in the general duties of the profession, are very numerous. These often arising from topical applications, we cannot doubt the propriety of giving a general currency to Mr. Stevenson's observations on the subject.

"To a person conversant with ocular complaints, it is really a matter of astonishment to witness the gross mistakes that are perpetually made in the selection, and proper management of external applications for the eye. For, nothing is more common, than to see astringent lotions resorted to in the very early stages of Opthalmia, by which the inflammation and pain become speedily and excessively exasperated.Whereas, if they had been withheld till the secondary symptoms had commenced, their utility would then have been as strikingly displayed, as in the former instance was the mischief they occasioued. Indeed it has been doubtless owing to the casual employment of the tonic class of medicines, during the chronic state of inflammation, that many boasted nostrumis of this description are indebted for their reputation, in the cure of morbid affections of the eye. I should not, probably, be incorrect in asserting that, more injury has resulted from injudicious officiou nesss in this particular, than from all other measures which have been adopted for complaints of that organ. Innocent as a common poultice is gene. rally esteemed, I have, in several instances of Ophthalmia, seen it ap plied with the lamentable effect of causing, in some instances, the forma tion of abscesses between the lamelle of the cornea, which not unfre quently end in incurable blindness, by the opacity they leave behind them;' and in other cases, it has occasioned a speedy ulceration, and consequent rupture of the cornea, and staphyloma. In fact, a good remedy untimely applied to the eye, has often rendered its diseases, which were at the time scarcely uneasy, absolutely incurable. And I am persuaded that, less mischief would in general arise, were every kind of application for the eye withheld, than from employing improper ones. And thus it has scarcely ever happened, that an appropriate collyrium has been used for the disease under consideration. Amongst the different formulæ prescribed for it, the Zincum vitriolatum has almost invariably been the efficient ingredient, on the supposition doubtless, that astringents alone were required with a view to brace the fancied relaxation of the organ. From the amplest experience of the effects of that plan I dare maintain, that till the plenitude of the vessels is diminished by proper evacuations, it uniformly does harm. Indeed, I have really my doubts, whether eye, waters are at all desirable, during the existence of the great tenderness

of sight. If any are advisable, I would recommend such only as are ealculated to allay action, and appease pain, as the different preparations of lead; of which probably the best is composed of the cerussa acetata gr. j. dissolved in 3j. elder flower water, and rendered perfectly limpid by the addition of a few drops of distilled vinegar. When used, it should be made a little warm, by immersing a cup, containing some of it, in a bason of boiling water. For I must repeat, that cold applications manifestly do harm in the early stage of this complaint, probably by constringing the exhalent pores of the cornea, and by propelling the blood from the superficial, to the deep-seated vessels of the eye, already in a preternaturally turgid condition. And, if any good effects are to be derived from the lotion. it must be repeated frequently during the day.

I trust I shall be pardoned for the dig ession, if I cursorily make a few practical remarks on the composition of eye waters. According to the manner in which they are occasionally prescribed, I am convinced that they are mischievous, when employed in cases of ophthalmia, or of great irritability of the eye. I allude to the custom of making them with the oxyds of metals, or other rough and insoluble powders, or with liquids, which though pellucid individually, yet when mixed together, suffer an inmediate decomposition, and in consequence, the eye water is rendered more or less turbid and inert. Indeed, nothing is more common than to see the cerussa acetata dissolved in common water, by which the lotion becomes instantly opaque, and the greater part of the lead is soon precipitated in form of a whitish calx. Must not the rough ingredients above alluded to, stimulate the exquisitely irritable cornea in some degree like so many heterogeneous particles of sand? Sometimes the tinctura, or the vinum opii, is added to an aqueous vehicle, the resinous particles of which separating from the watery menstruum, they are introduced into the eye, and adhering to some part of the globe, excite in it no small degree of irritation. However refined this may appear to the inaccurate observer, I must declare that, I have personally witnessed very acute pain having beer brought on by this apparently trivial cause, which has not ceased, until the removal of these little filaments of opium.*

In a word, I hold it to be an invariable maxim, that eye waters should be rendered perfectly transparent before using, either by the addition of an appropriate solvent, (if the active ingredient be derived from the mineral kingdom, taking care that it coincides with the intention of the remedy), or else by filtration through paper.

But although I am not strongly prepossessed in favour of any kind of collyria, from a satisfactory experience of their utility in weakness of sight, before the exquisite sensibility of the retina is relieved by the plan of depletion above recommended, yet after this object is once fully at tained, the vessels of the eye will then require astringents to impart increased tone and energy. Otherwise, a relapse would be very apt to occur, from the blood again accumulating in vessels, relaxed by long continued over-distension.

Of the applications best adapted to accomplish that purpose, I may name a weakish solution of Zincum vitriolatum, dissolved iu camphorated mixture, or in rose water, and filtered. But I think a still more

I have met with similar effects from neglecting to pass an infusion of digitalis, prepared with fine powder of the plant, through linen cloth before using it.

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