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treatment, and the reparative power of nature is undoubtedly greatly assisted by stimulating applications, massage, and the like, but we soon reach the limit of our usefulness; and for old opacities, little remains but surgical interference. This is frequently inadvisable, and always unsatisfactory.

Corneal transplantation offers an inviting field, but thus far has accomplished but little. The clearing of the cornea surrounding the transplanted area will, it seems, be more frequently obtained than the permanent transparency of the engrafted tissue. Even were it a more generally successful operation, its utility is limited to those cases in which no benefit can be obtained from an iridectomy, and where the opacity does not extend through the entire thickness of the cornea.

It is impossible to obtain satisfactory statistics as to the frequency of lesions of transparency of the cornea. Having once applied for relief and receiving little encouragement, patients do not drift from one eye clinic to another, consequently the records of these institutions. would lead us to infer that such cases are more rare than is actually the case; but when we remember the vast number of cases of keratitis that we daily see, many of them so severe that they must leave permanent traces of their existence, we are convinced that corneal opacity must be a very common affection.

It is with great pleasure that I present a contribution to the therapeutics of these unfortunate cases, which I believe to be of some real value, and that offers at least some hope of improvement in nearly every case.

The method of treatment to which I refer, is the application of galvanic electricity directly to the surface of the cornea. So extravagant have been the claims of some of the advocates of electrotherapeutics that the profession in general, having been disappointed in their endeavors to justify these statements by their own experience, are inclined to look with great distrust upon any plea for the further extension of this method of treatment.

I have, therefore, endeavored in making the experiments with which I have been for some time engaged, to avoid as far as possible all errors which may arise from careless observation or too vivid imagination on the part of patient or physician.

In testing the vision from time to time I have used artificial illumiation of unvarying brilliancy, and, by frequently changing the testletters, have endeavored to prevent the patient from committing them to memory.

I have measured the vision exactly in each instance, using a steel tape as a measure of distance, to obtain greater accuracy.

When in any case I have used a mydriatic, either to ascertain what

vision could be obtained through the clear cornea surrounding the scar when the pupil was dilated, or to better observe the condition of the lens, iris, etc., I have either taken no records of the vision till the effects of the mydriatic have passed away, or have indicated in my records that the pupil was dilated at the time the record was made.

During treatment the visual record was always taken before the instillation of cocaine or the application of the current.

The idea of using galvanism for the removal of corneal scars first suggested itself to me from noticing the good results obtained by gynæcologists in some cases of old inflammatory deposits in the pelvis. It seemed to me reasonable that a similar absorption of repair-tissue could be brought about in the cornea, and that electricity would prove a most valuable therapeutic agent, could it be so applied as to produce sufficient molecular disturbance in the cloudy area to bring about its absorption, while at the same time it should have no ill effects upon the healthy tissue of the eye.

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I concluded that a small electrode applied to the surface of the cornea was indicated, since by this means a current of great density would be applied directly to the diseased point and since the greatest molecular activity is induced at a point directly in contact with the electrode, the indication of strictly limiting the current's action would be best fulfiled. I apply the other electrode to the cheek, making the path of least resistance through the soft tissues of the face, in order

not to bring the intra-cranial organs nor more of the globe than necessary within the circuit. By reference to Fig. I., the advantage of the small electrode in immediate contact with the cornea may be readily seen. The current is represented as consisting of a certain number of strands, in both instances the same. It is apparent that the current is brought to bear much more directly upon the cloudy area in A than it is in B.

(Fig. I.)

It was my original intention to make use of some of the preparations of mercury commonly employed in the treatment of corneal opacities, hoping by the combined action of mercury and electricity to obtain better results than from the use of either agent alone. I made several experiments, usually with the yellow oxide, but found it well nigh impossible to find any vehicle for the mercury which would at the same time act as a good conductor and prove unirritating to the eye. I finally hit upon an expedient which has proved very satisfactory: it was to make the tip of my electrode of silver, which plunged into a bath of metallic mercury, would form with it an amalgam and hold a globule of mercury on the end of my electrode. This makes a smooth and adjustable cushion to apply to the cornea; it fits itself perfectly to the corneal curve, and precludes the possibility of any unevenness on the surface of the electrode damaging the cornea. Whether or not the mercury in any way assists the action of the current it is quite impossible to say, but be this as it may, it furnishes in practice a most satisfactory tip for the corneal electrode.

After trying various forms of electrodes, I find the most desirable model to be the one shown in Fig. II. It consists of a small silver bar, a, 12 mm. in length, insulated, except at the ends, by a hard rubber shell; the exposed surface at the lower extremity is slightly concave, the better to hold the globule of mercury, and is 7 mm. in diameter. The upper extremity carries a thread which screws into a metal collar at b, allowing the tips to be changed when corroded by the action of the mercury. The collar is attached to a copper spring, c which still further protects the cornea from injury when the electrode is moved in the fingers, and at the same time being perfectly flexible, allows the tip to be adjusted to any desired angle, which greatly assists the convenience of application. The spring is fastened to a hard rubber handle, d, 10 cm. in length and 1 cm. in diameter, through which a conducting wire is carried to the binding post, e, at the upper extremity. (Fig. II.)

I have found this electrode most convenient in practice, and fulfiling all the desired indications.

In the immediate application of electricity to the cornea some form of galvanometer is essential. My first few experiments were conducted

without one, and I soon became convinced that an accurate measurement of the current was demanded alike for the safety of the patient and to insure the utility of the treatment. For the small current upon an anesthetized cornea produces no sensation whatever, therefore the patient cannot inform you whether or not the current is passing. Should the battery be reasonably constant and always in repair, an ideal condition scarcely to be hoped for in practice, the resistance in different patients, and even in the same patient at different times, varies so enormously that it is impossible to judge even approximately the amount of current which the patient is receiving. I have obtained from the same number of cells used, as nearly as I could judge under similar conditions, currents ranging from 4 to 3 m. a.

FIG. II.

I am using a milliampèremeter made by Fleming, of Philadelphia. This instrument will measure 4 m. a., and has proved extremely satisfactory. Beside a variation of resistance from varying conditions of conductivity at the beginning of an application, we have to take note of the diminution in resistance during the passage of the current. Erbe' has experimentally demonstrated this, and the deflection obtained during the continuous passage of the current, by first increasing and then diminishing the number of cells, is shown in the following table:

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To avoid the annoyance from such variations in resistance, I found it convenient to use a rheostat; and since the satisfactory instrument I am at present using is the only one with which I am familiar, sufficiently delicate to be available with the extremely small currents with which these applications are made, a brief description may be of interest.

The rheostat was made by Mr. J. A. Barrett, and depends in principle upon the diminished resistance, under pressure, of a pledget of cotton permeated with powdered graphite. Its construction may be

1 Electro-Therapeutics, p. 48.

better understood by reference to Fig. III. It consists of a hard rubber cylinder, a, containing the cotton, which rests between a metal plate at one end of the cylinder connecting with the post, b, and a metal plunger, the rod from which passes through a thread at c, and terminates in the milled head d. By the rotation of a the density of the cotton, and consequently the resistance offered by the rheostat, may be increased or diminished at will. Wires conduct from b and e to the binding posts ƒ and g, by which the rheostat is included in the circuit. (Fig. III.)

FIG. III.

In making an application, I stand behind the patient whose head is thrown back in a reclining chair. I give one electrode to the patient and direct him to press it against the cheek on the same side as the eye to be treated. I then place the binding post of the eye electrode against the patient's tongue and turn the rheostat, until the needle indicates the strength of current I desire to use, when, after dipping it in a bath of mercury, I place the electrode upon the cornea, which has been anesthetized by the previous instillation of cocaine. The rheostat is now intrusted to an assistant, who carefully watches the needle of the milliampèremeter, and by turning the screw of the rheostat, maintains a uniform current during the application. With the thumb and first finger of the left hand the lids are separated sufficiently to prevent their coming in contact with the electrode, since a current easily tolerated by the cornea is painful and irritating when passing through the margin of the lids. The electrode is held with the right hand, gently, in contact with the cornea, and a careful watch is kept during the application that the contact is not broken nor too firm a pressure made against the cornea.

It is perhaps unnecessary to test the current by first passing it through the tongue, which offers practically the same resistance as the eye, but as there is always the possibility that by some accident the rheostat or milliamperemeter may be out of order or short-circuited, I think it safer to first try the current upon the tongue, where, if it is too strong, the patient will quickly inform you.

The cathode is applied to the cornea, being theoretically indicated for the stimulation I wish to produce.

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