are the causes of dark spectra, and of partial amaurosis. of the brain is well known to produce hemiopia.

Disease

Dr Delafield relates the case of an elderly gentleman, who afterwards became totally blind, one of whose early symptoms was, that in walking he imagined he saw objects on the ground which intercepted his path, and which he endeavoured to avoid by taking long and high steps. These spectra were perhaps fixed muscæ. On dissection, the eyes seemed in all respects sound, and had the plumpness and clearness of health. No mention is made, however, of any microscopical examination of the retina. The ventricles of the brain were greatly surcharged with fluid and the optic nerves to and from the ganglion opticum [chiasma ?] shrunk, or rather absorbed; so that they appeared flat, and were of a straw colour. Only the sheath of the nerve remained, the medullary substance having entirely disappeared.

§ 44. Symptoms coincident with fixed muscæ.

In most of the cases in which fixed muscæ are a prominent symptom, there will be found a combination of various other subjective symptoms; such as photopsia, or the sensation of coruscations and halos of light; floating muscæ; the retina unnaturally retentive of impressions; ocular spectra; the alternate disappearance and reappearance of small objects; hemiopia; partial and oblique vision; chrupsia; the sensation of an undulating cloud before the eyes, with occasional openings in it, through which small objects are seen by fits, and then are obscured again; bright objects exhibiting a tremulous, undulating light and shade; the edges of objects ill defined and shaggy, as if fringed with hoarfrost; perpendicular lines appearing disfigured, printed letters broken or indented, and circular objects deprived of their regular figure. What belongs to the fixed muscae must not be confounded with what depends on other causes. An interesting case of this mixture of symptoms, the reader may find recorded by the . patient himself, Mr Keir, in the Lancet for October 1, 1842. The case of Frofessor Boze affords another example of the same thing. Besides the sensation of a disc before one of his eyes, objects appeared curved, misshapen, and fringed; letters seemed broken objects were as if coloured blue and green; the disc grew broader and more opaque, and at last the vision in one-half of the retina was extinguished, the other half seeing as if through a thick fog.t

§ 45. Treatment of fixed musca.

Most of the cases of fixed muscæ are incurable, as may

be con

514.

*Notes and Additions to Travers' Synopsis of the Diseases of the Eye, p. New-York, 1825.

+ Histoire de l'Académie Royale des Sciences pour 1760, p. 54. Paris, 1766.

cluded from the nature of the efficient causes upon which they depend. The cases susceptible of treatment are most likely to be benefited by depletion of various kinds, mercury, iodide of potassium, and counter-irritation, followed up by general and local tonics, so as to relieve the over-distended state of the vessels, and restore them to their natural diameter. If the disease arises from the suppression of any habitual discharge, an attempt should be made to renew this, or to procure a substitute for it. The best local application is cold water, applied to the eyes and face by means of folded pieces of cloth. Richter remarks, that by this means alone, the disease has sometimes been completely removed; an instance of which, indeed, seems to have occurred in the case of Boerhaave, as thus related by himself. "In aestu solis sumino mihi equitanti per loca arenosa enascitur magna macula in fundo oculi. Cogitanti succurrit mihi, medicamentum optimum fore aquam frigidissimam, quae a me applicata remedio fuit: Inflammatio ergo procul dubio erat in fundo oculi, et saepe etiam fit tali in casu, hinc optimum remedium est, quod subito retropellendo omnia vasa constringit, ut aqua frigida."* The length to which this paper has extended must be my excuse, for not entering into a detailed consideration of the remedies above mentioned.

$ 46. Conclusion.

I must here quit the highly interesting and important subject, the present amount of our knowledge of which I have thus attempted methodically to digest and arrange. While I have endea

voured, as much as possible, neither to introduce extraneous notions into the consideration of it, nor to exclude any part of the case before us, I am fully sensible that much remains to be investigated respecting the VISION OF OBJECTS ON AND IN THE EYE, and that, in fact, by attempting thus to discriminate what is strictly known upon the subject from what is merely conjectural, I have done little else than pioneer the way for still more strict and scientific inquiries. "In rebus quibuscumque difficilioribus non expectandum, ut quis simul, et serat, et metat, sed praeparatione opus est, ut per gradus maturescant."

Fig. 1. Illustrating experiment 2d, p. 42.

Fig. 2. Showing the appearance of the pearly spectrum, (a); the watery spectrum, (b); and the insulo-globular spectrum, (c), p. 48.

Fig. 3. Showing the appearance of the tubulated spectrum, p. 53.

Fig. 4. Illustrating description at p. 54.

Fig. 5. Illustrating experiment 10th at p. 58.

Fig. 6. Illustrating description at pp. 62 and 63.

*

Op. cit. p. 62.

Glasgow, 30th December 1844.

VOL. LXIV. No. 164.

G

ART. III.-On Inflammation of the Membrane of the Aqueous Humour of the Eye. By ALEXANDER WATSON, M. D., F. R. C. S. E., Consulting Surgeon to the Royal Infirmary, and Surgeon to the Eye Infirmary, &c. &c. Edinburgh.

THE general characters of the ophthalmia had been observed by the earliest physicians, and by them handed down from generation to generation until our own times, with very few additional observations.* It has therefore been reserved for the nineteenth century to make those nicer and more important specific distinctions which characterise the ophthalmic surgery of the present day. And although in this path the German surgeons led the way, yet those in Britain have not been slow in employing their talents and acute observation to extend our knowledge of these diseases, as well as to apply their judgment and skill in giving precision to the treatment of them.

To the accounts given concerning those diseases of the eye, which have been so elegantly described and delineated by Dr Wardrop, in his essays on the Morbid Anatomy of the Eye, published about thirty years ago, very little has since been added. But some of these diseases have been subdivided into species and varieties; several additional morbid conditions have been described; and the treatment of ophthalmic diseases generally, has been more completely detailed, in the numerous systematic treatises which have been published since the commencement of the present century. +·

The internal ophthalmice or inflammation of the internal parts of the eye, were, in consequence of their obscure symptoms and difficulty of their investigation, the latest to be recognised and described. They are also the most important, being the most dangerous to vision; yet their presence is not easily detected, and they are often insidious in their invasion, while they are at the same time tedious in their progress and difficult to remove.

* Galenus de locis affectis, iv.

Paul of Aegina, Book iii. xxii. The medical works of Paulus Aegineta, translated into English, with a Copious Commentary by Francis Adams, Esq. surgeon. London, 1834, 8vo.

Banister, Richard.

London, 1622, 12mo.

A Treatise of 113 Diseases of the Eyes and Eyelids.

Maitre-Jean. Traité des Maladies de l'Oeil et des Remedes propres pour les guerir. Troyes, 1707, 4to.

St Yves. Nouveau Traité des Maladies des Yeux. Paris, 1722. Janin. Memoires et Observations anatomiques et physiologiques sur l'Oeil et sur les Maladies qui affectent cet organe, etc. Paris, 1772.

Benedictus, Traug. Gul. Gust. de Morbis Oculi Humani Inflammatoriis. Lipsiae, 1811, 4to.

See the Treatises of Travers, Lawrence, Mackenzie, Tyrrell, Middlemore, and Watson.

Indeed, when they are of a chronic character, they may proceed to a considerable extent before their existence is suspected by the patient or recognised by the surgeon; owing to the sight being very gradually impaired, and the eye presenting to an ordinary observer little or no visible morbid change.

Another important peculiarity of the internal ophthalmia consists in the disease being seldom confined to one part of the organ. One part or texture may at first be affected, but very soon the neighbouring parts participate in it. This extension of disease is readily accounted for by the close and intimate connection which exists between the internal parts of the eyeball, and their dependence on each other. A striking illustration of this was lately afforded in the cases which we had an opportunity of seeing, of internal ophthalmic which occurred after the epidemic fever which prevailed here as well as in Dublin and Glasgow. A slow insidious inflammation of the internal parts of the eye in some cases supervened during or after convalescence from the fever, in which it obviously attacked first the retina, then extended to the choroid coat, the iris, vitreous humour, and cornea, in succession, without causing much pain, or inducing the appearance of inflammation externally, though vision was generally much impaired.

Inflammation of the serous membrane which encircles the aqueous humour of the eye is alluded to by Dr Wardrop only as a highly probable occurrence in the first volume of his essays; but is more fully described in the 2d volume, as also in the 4th volume of the Medico-Chirurgical Transactions. Still, the accounts of the disease there given are imperfect, and the modification of it about to be described is not mentioned.

This disease we find afterwards described by Baron von Rosas of Vienna, under the name of kerato-iritis.

In the year 1825, I had the honour to submit, to the MedicoChirurgical Society of Edinburgh, a short account of an affection of the eye, under the name of chronic inflammation of the iris, which was afterwards published in the Transactions of the Society. (Vol. ii.) I adopted this name because the most obvious morbid changes were observed in the iris; although I at the same time stated it to be my opinion that, the disease might rather be considered to be an affection of the membrane of the aqueous hu

mour.

The disease which I described in the essay referred to, consisted in chronic inflammation affecting the more delicate internal parts of the eye, producing effusions of lymph in the chambers of the aqueous humour, followed by irregularity in the form and contraction of the pupillary aperture of the iris, accompanied by loss of sight, to a greater or less degree, according to circumstances. The complaint was also described as insidious in its invasion, slow

in its progress, and, in the cases which I had seen, (which has been of old standing) intractable in its treatment. It also showed the analogy which existed between this and inflammation of the serous membranes of other parts of the body.

Since that time I have had many opportunities of verifying my remarks. But by an improvement in the glasses used for examining such diseases, I have been of late enabled to extend my observations so as to acquire a more intimate knowledge of some of those diseases, whose distinctive characters are so minute that they elude the powers of unassisted vision.

By Dr Mackenzie the disease under consideration is described as a rare ophthalmia," under the title of Aquo capsulitis, in his Treatise on the Eye, published in 1830; but the description of the disease and its treatment are chiefly taken from the essays of Dr Wardrop.

Allusion is made to this disease by Mr Lawrence in his Lectures on the Eye, published in the Lancet in 1826, (Lect. XVI.) But a more full and complete account of it is given in the second edition of his Treatise on Diseases of the Eye, published in 1841. The disease is also shortly described by Mr Tyrrell in his work on the Eye, published in 1840.

Having premised this account of the history of that species of internal ophthalmia affecting the membrane of the aqueous humour, I now proceed to describe a frequent and interesting modification of the disease, attention to which is of much practical importance; for if, on the one hand, it is detected in its early stages, it may be completely cured; while, on the other, if it is allowed to proceed without being recognised and proper remedies applied, it is certain to terminate in causing great imperfection of the sight, or in producing complete blindness.;

Perhaps the best mode of explaining the symptoms, characters, and progress of this disease, and its appropriate treatment, is, in the first place, to select a few cases, and then to make a few remarks upon them.

CASE I.-A. B., aged 20. A young lady of delicate constitution; has frequently had attacks of ophthalmia in spring.

August 26th. Is affected with chronic inflammation of both eyes, which has existed during the last four months. The sight has become very obscure, of both eyes, but especially of the left. There is a deep-seated red zone around the cornea of both eyes, and a few enlarged conjunctival vessels are seen to proceed forwards to the cornea. This increased vascularity of the eyes is easily augmented by any cause of excitement, by the exercise of the organs, or by the application of cold.

The lower part of the cornea of both eyes, but particularly the