_Third step._ Consists in the removal of the tumour. Care must be taken to displace the external rectus to one side so as to avoid injury to it as much as possible. If the case should be one of an optic nerve tumour, for which the operation is most frequently performed, the optic nerve is divided close behind the globe. The tumour is freed from the surrounding ciliary nerves and the ophthalmic artery and brought up into the wound as much as possible. The optic nerve is then divided at the apex of the orbit and the tumour removed. The wound in the periosteum of the outer wall of the orbit is closed with a catgut suture, the bone, together with the soft parts, replaced in position and the skin wound closed by sutures. A drainage tube should be inserted for at least twenty-four hours. =Complications.= 1. _Proptosis._ The operation is liable to be followed by great proptosis as the result of hæmorrhage into the orbit. If the optic nerve has been removed, the globe may be dislocated forwards between the lids and come in contact with the dressings. 2. _Corneal ulceration._ As the cornea is frequently anæsthetic from division of the ciliary nerves, ulceration is very liable to follow. It is, therefore, desirable in many cases to stitch the lids together after closing the skin wound. 3. _Defective outward movement in the globe_ is of frequent occurrence, owing either to injury of the external rectus or the sixth nerve, or to involvement of them in the scar tissue. Stitching the periosteum together obviates the latter to a certain extent. 4. As the wound cicatrizes a certain amount of _enophthalmos_ is very liable to result. EVISCERATION OF THE ORBIT =Indications.= This operation is usually performed for some form of new growth originating either in the eye or the orbit. =Operation.= This may be modified (1) according to the _position_ of the growth. In severe cases of rodent ulcer and sarcomatous growths, which involve the lids, it is desirable that the lids should be removed with the tumour; but in cases of tumour of the optic nerve, or disease situated far back in the orbit, and not involving the lids or conjunctiva, these structures may be retained, since a much better socket is thus obtained. (2) The _nature_ of the growth. In simple tumours, such as nævi and some cases of arterio-venous aneurism which have failed to yield to other treatment, the incomplete method, in which the lids are retained, is all that is necessary, but in malignant cases they should be removed.