The difficulty of diagnosis in cases or orbital pulsating tumors is thus very great. In examining a case we must note the effect of :-(1) compression of the common carotid on the same side; (2) steady pressure on the eyeball through the closed lids, whether on removing the pressure the former state is slowly or quickly reproduced; (3) the seat of greatest pulsation, whether the pulsation is strong or weak, the effect of posture, the presence of a bruit heard by the stethoscope or at a distance through the air, and the character of any sound heard by the patient in his own head; (4) pain and inflammatory symptoms and history of injury; pain is often severe in cases of traumatic aneurism with extravasation and orbital inflammation.

Ligature of the common carotid has been practised with good results in a considerable number of cases of pulsating orbital tumor; but the treatment of these cases does not belong to the ophthalmic surgeon.

(5.) A tumor which fluctuates freely, does not pulsate, is free from inflammatory symptoms, and not connected with the frontal sinus, may be a chronic orbital abscess (see also p. 61), a hydatid, or a cyst containing bloody or other fluid and of uncertain origin. An exploratory puncture should be made after sufficiently watching the case, and the further treatment must be conditional. Perfectly clear, thin fluid probably indicates hydatid, and in this case the swelling is likely to return after puncture and the cysts to need removal through a freer opening. The echinococcus hydatid (the only large one infesting man) often contains daughter-cysts, some of which escape puncture. Suppuration may take place around any hydatid.

(6.) Examination leads to the diagnosis of a solid tumor limited to the orbit. We have next to determine, if possible, in what part of the cavity the growth began, whether in the eyeball or optic nerve, or in some of the surrounding tissues.

We therefore examine the globe for symptoms of intraocular tumor, particularly detachment of retina, cataract and glaucoma (p. 246).

Solid growths independent of the eyeball may arise (a) from the periosteum; these are firmly attached by a broad base, are generally malignant, and seldom admit of successful removal. (b) The lachrymal gland is the seat of various morbid growths, including carcinoma (compare p. 61); the diagnosis is often easy, since the chief portion of the growth will be in the position of the gland, and a large part of it can be explored by the finger. Although such a growth is often attached firmly to the orbital wall, its position, lobulated outline, and well-defined boundary will often lead to a correct conclusion. Tumors of the lachrymal gland should always be removed if they are increasing; for we can never feel sure that they are innocent. (c) Solid tumors originating in some of the softer orbital tissues, especially the form known as cylindroma, or plexiform sarcoma, occur more rarely. (d) Tumors of the optic nerve are rare; they have occasionally been extirpated without removing the globe; they usually cause blindness and neuro-retinitis, but no absolutely pathognomonic symptoms.

When the orbital tumor is found during operation to be adherent to the wall or to infiltrate the tissues around it, chloride of zinc paste should be applied on strips of lint, either at once, or the day after the operation, when oozing has ceased and suppuration has not yet begun. If the periosteum is affected it is to be stripped off and the paste applied to the bare bone. Hemorrhage from the apex of the orbit, after removal of the globe and tumor, can always be controlled by perchloride of iron and a firm compress.

In every case of suspected primary orbital tumor (unless the growth be quite clearly limited to the lachrymal gland), the question of syphilis must be very carefully gone into.

Neither periosteal nor cellular nodes are common in the orbit, but both varieties occur sometimes, and disappear under proper treatment.

D. INTRAOCULAR TUMORS.

By far the commonest forms are glioma of the retina and sarcoma of the choroid.

Glioma of the retina is always a disease of infancy or early childhood, the patients being generally under two years old when first brought for treatment; it may, however, be present at birth, and may begin as late as the eleventh or twelfth year. It is a very soft small round-celled growth from the granule layers of the retina, and either grows outwards causing detachment of the retina, or inwards into the vitreous; often several, more or less separate, lobules are present. It runs a comparatively quick course, filling the eyeball in a few months, spreading by contact to the choroid, and thence to the sclerotic and orbit. It has an especially great tendency to travel back along the optic nerve to the brain; it may cause secondary deposits, in the brain and in the scalp, and more rarely in distant parts. If the eye be removed before either the optic nerve or the orbital tissues are infiltrated, the cure is radical, but in the more numerous cases, where the patient is not seen till what may be called, clinically, the second stage (see below), a fatal return occurs in the orbit or within the skull. Glioma sometimes occurs in both eyes one after the other, and in several children of the same parents.

The earliest symptom is a shining whitish appearance deep in the eye, and the child's mother then soon finds that the eye is blind. As neither pain nor redness is present the case is often not brought for advice until several months after this discovery is made. When the eye begins to protrude, or becomes red and painful, the child is brought. In this (the

second) stage there is generally some congestion of the scleral vessels, and a white, pink, or yellowish reflection from behind the lens (which remains clear), some steaminess of the cornea, dilatation of the pupil and increase of tension; and there may be enlargement or prominence of the eyeball. On focal examination some vessels can generally be seen on the whitish background, and white specks of calcareous degeneration are sometimes present.

Cases are not very uncommon in young children, in which the above appearances are closely simulated by inflammatory changes in the vitreous, often with detachment of the retina, and the differential diagnosis is sometimes impossible. The presence of iritic adhesions, the history of a definite inflammatory attack preceding the white or yellow appearance in the pupil, and the fact that the tension is normal or subnormal are the points in which these cases differ most from glioma; but when there is any doubt the eye should be excised.

Sarcoma of the choroid (including the ciliary body) is a growth of late or middle life, being rarely seen below the age of 35. The majority of these tumors are pigmented (melanotic), some being quite black, others colored to different degrees in different parts, a few are quite free from pigment. Some are spindle-celled or mixed, others composed of round cells; some are truly alveolar, but in many specimens there is very little connective-tissue stroma, and no very defined arrangement of the cells. These tumors are moderately firm but friable; some are very vascular, and hemorrhages often occur. The tumor generally grows from a broad base, and forms a well-defined rounded prominence, pushing the retina before it; and hemorrhage or fluid effusion generally takes place round the base of the growth, so that the retinal detachment is usually much more extensive than the tumor. These tumors often grow slowly so long as they are wholly contained within the eye; two, three, or more

years may pass before the growth passes out of the eye and invades the orbit. Though this does not usually occur till the globe is filled to distension by the growth, it may happen much earlier, the cells passing out along the sheaths of the perforating blood vessels, and producing large extraocular growths, while the intraocular primary tumor is still quite small. The lymphatic glands do not enlarge, but there is great danger of secondary growths in distant organs and tissues, especially the liver, and this risk is not entirely absent even when the eye tumor is quite small. Hence early removal is of the utmost importance, and a good, though not too confident, prgonosis may be given when the optic nerve and tissues of the orbit show no signs of disease.

Symptoms and course. If the case is seen early, when defect of sight is the only symptom, the tumor can often be seen and recognized by its well-defined rounded outline, some folds of detached retina often being visible near it. There will seldom be either pain or redness, and the pupil, cornea, and eye-tension may be quite natural. But sooner or later the tumor in its growth sets up symptoms of acute or subacute glaucoma with much pain, and causes secondary cataract, and it is now that relief is usually sought (second stage). Unless some part of the tumor happen to be visible outside the sclerotic or project into the anterior chamber, a positive diagnosis cannot now be given on account of the opacity of the lens, although by exclusion we may often arrive at great probability. If the eye be left alone, or iridectomy be performed, glaucomatous attacks and pain will recur and the eye will either enlarge and gradually be disorganized by the increasing growth, which will then quickly fill the orbit and fungate, or a deceptive period of quiet may follow, and perhaps even some shrinking and reduction of tension may occur, after which the growth will make a fresh start and become apparent. It is chiefly in very old patients that this slow course is noticed. Sarcoma is especially likely to form