to the head. When I saw him, three days after its commencement, there was a distinct erosion, in two or three different places, with a good deal of muddiness of the cornea. There was also a bright redness on the white of the eye; he had intense pain in the head, accompanied with excessive languor and debility; his tongue white, and a quick hard pulse. The obscurity of the cornea instantly disappeared by the evacua tion of the aqueous humour, and the pain of the head was alleviated. He was bled at the arm profusely, and the eye was fomented. On the following day all the symptoms were much relieved; and in a few days the ulcer healed, and the eye recovered perfectly, without the aid of any local applications.

Observations on the Cataract.

By BENJAMIN TRAVERS, Esq. Demonstrator of Anatomy at Guy's Hospital. Surgeon to the Hon. East India Company, and to the London Infirmary for Diseases of the Eye.

[From the London Medico-Chirurgical Transactions for 1813.] OPACITY is the result of inflammation in a transparent part, as is seen in the scarf-skin, the conjunctiva, the cornea, the crystalline and vitreous humours of the eye, and their membranes. If the inflammation is arrested before it reaches the stage of effusion, the opacity, which probably depends upon the turgescence of the colourless vessels, is partial; and the part recovers its transparency when the inflammatory action ceases. This is proved by the haziness of the cornea in acute inflammation of the conjunctiva, accompanied by dimness of vision; a symptom which gradually goes off after the inflammation is subdued. When effusion has taken place even in a moderate degree, as in the nebula of the cornea, the opacity is more slowly removed, and seldom perfectly, even long after the inflammation has ceased. Where a deposition has taken place in consequence of a breach of the natural texture, as

after an ulcer of the cornea, the opacity, greater or less according to the extent of the deposition, is permanent. Inflammation is the only cause of cataract open to observation. The simplest example of it is afforded by the accidental wound of the crystalline by a penetrating instrument; in this case the opacity is partial, and the cicatrix of the wound is the centre of the opake spot. Another frequent example is the cataract following acute inflammation of the choroid and iris, whether arising spontaneously or from injury, as a violent contusion of the eye. In this case the opacity is sometimes diffused over the capsule of the lens which adheres to the contracted pupil; sometimes it is only a central spot, and the iris seems to adhere to a transparent part of the capsule.

A conformation of body favouring a determination of blood to the brain, or frequent exposure of the eye to the stimuli of heat and light in more than ordinary intensity, or the habitual vision of minute objects in a depending position of the head, by which an undue proportion of blood is thrown upon the organ, commonly induce opacity of the crystalline or of the retina; which in one species of amaurosis turns of a green yellow colour, and becomes distinctly visible.

Cataracts are very frequently of spontaneous occurrence in persons of advanced years, in whom no signs of inflammation have preceded the complaint.

Transparent parts obviously tend to become opake in age, as may be instanced by the want of clearness of complexion in old persons, and the arcus senilis, as it is called, which is an opacity without inflammation encroaching upon the cornea. The very minute serous vessels of the crystalline run in the cellular substance which unites the lamella. This interstitial texture is probably absorbed in age, and the vessels may be gradually obliterated by compression;* but this must be matter of conjecture.

* A change in the action of so minute and remote a system of vessels we should not expect to discover otherwise than by its local effects. Changes in other organs, similar to those which produce the different kinds of cataract,

Cataracts are also formed in utero, and I have rarely observed in the subjects of congenital cataract other marks of deranged or defective organization. Some other and more subtle cause of opacity must therefore be admitted.

The cataracts of new-born children and of aged persons exhibit very opposite appearances. In congenital cases the opacity most frequently appears in the central nucleus, the interior denser structure demonstrated in the healthy lens by Petit, and is either stationary, or enlarges equally and slowly in a circle. This nucleus is sometimes not bigger than a pin's head in the centre of the transparent lens; but more commonly it is of the size of the contracted pupil, so that the child habitually knits his brows, or screens his eyes with his hand, to obtain that state of the pupil which he finds necessary to his vision. The fluid and capsular cataracts are exceptions to this observation. It is well known that adult subjects of cataract see better in moderate than in strong light, but in a much less degree; for the opacity is in them more diffused, so as very faintly, if at all, to exhibit a nucleus; and a dilatation beyond a natural one, I mean that obtained by the belladonna, though it enlarges somewhat the field of light, seldom permits of vision. The opacity commonly appears of equal consistency from the origin of the complaint, and in its progress the light is shut out from the whole sphere of the pupil. The hard cataract affords a partial exception to this remark, in which the nucleus, though imperfectly defined, is generally to be distinguished.

The opacity is sometimes simply capsular, which is known by the uniform nebulous tenuity of the opake membrane stretched over the transparent lens, and rendered more distinct by the dark tint reflected from the choroides. The cata

are familiar to our ordinary experience. Thus we see the matter of secretions altered, loose interstitial texture consolidated by excess of deposition, or obliterated by absorption; changes, which, in lymphatic glands, and parts framed for less nice and delicate purposes than the organ of vision, are less obvious, although equally subversive of their functions

ract appears to be prominent in the pupil, which is sometimes slightly irregular. In this case, which is considered to be an incipient state of the cataract, as by the consequent opacity or absorption of the lens it becomes more dense and distinct, the quantity of light admitted is considerable.

More frequently the opacity is simply lenticular, which is known by the cataract appearing more dense, voluminous, and varied in its colour and texture, and in relation to the plane of the iris, deeper seated; by the circularity of the pupil, and the greater degree of blindness in the natural state of dilatation. The motions of the pupil being regulated by the quantity of light which is admitted to the retina, its size depends upon the texture and bulk of the opake lens, i. e. a very dense cataract keeps it dilated by excluding light from the retina; a very bulky one by mechanically distending it. In most cases of congenital cataract, and in some of mature age, the dilatation by belladonna discovers a defined margin to the opacity, and a transparent circle beyond it, and therefore adds considerably to the patient's perception of light. I have known patients in this state, who were of an age to judge for themselves, decline the operation, content with the vision they enjoyed by the use of the belladonna. In such cases, however, a tolerable vision has been previously enjoyed, owing to the smallness of the opake nucleus compared with the transparent portion of the lens. And in all cases the vision of near objects is confused, if not totally bedimmed, by the enlargement of the pupil with the belladonna, although that of distant ones is clear and distinct. Where a transparent circumference has been discovered after dilating the pupil by the belladonna, I have never seen the capsule opake, and I believe this black rim may be considered as diagnostic of the transparency of the capsule. Where the lenticular opacity is diffused, this sign of a transparent capsule is of course wanting.

The opacity is sometimes much deeper seated, so that you look at it through the transparent capsule and lens. It is here generally circumscribed, but irregularly shaped; and often,

from its tenuity and depth of situation, escapes the observation even of oculists. This is usually considered to be a third seat of opacity, distinct from the former, viz. in the posterior covering of the lens. I do not find, upon repeated and strict examination, any proper capsule investing the lens, i. e. which admits of being removed with it. It may be necessary to a right understanding of this structure, briefly to describe it. The tunic of the vitreous humour advances to the ciliary body, there it separates into two lamina, which, when contiguous to the margin of the crystalline, adhere closely to each other, forming the sacculated circle (canal godronné) described by Petit, which is capable of being inflated around the margin of the lens. This canal corresponds in breadth to the breadth of the ciliary processes, and is marked by them anteriorly. The anterior lamina, which is the more dense of the two, covers the crystalline in front; the posterior lines the fossula of the vitreous humour. There is no communication betwixt the canal of Petit, the vitreous humour, and the crystalline capsule. They are all distinct from each other, and must be inflated distinctly, if perfect. The crystalline, it will appear from this description, is incased in a duplicature of the vitreous capsule. The different texture of these laminæ adapted to their respective uses, (the one properly belonging to the crystalline, and supporting the whole lens in its place; the other proper to the vitreous, and covering a very small portion of the humour, which is sufficiently supported by the crystalline itself) and likewise the close investiture of the margin of the lens, which interrupts continuity, for it prevents the passage of air, explain why they are so seldom similarly af fected in disease. The posterior opacity before described is therefore seated in the proper tunic of the vitreous humour. Thus much on the situations of the opacity forming cataract.

The varieties of consistency, colour, and figure, are numerous. With regard to consistency, we have the fluid or milky, the flocculent or fleecy, the caseous or doughy, and the compact or hard cataract. The fluid lens is, I believe, rarely