3. _Recurrence of the mucocele or lachrymal abscess._ Occasionally the mucocele may re-form, or an abscess result after removal of the sac. This is due either to a piece of sac-wall being left behind, or to the relining of the cavity with epithelium from the cut end of the duct. It is particularly liable to occur in cases of a tuberculous nature. Firm pressure with the dressings after the operation is the best method of preventing the cavity relining with epithelium. If the condition has arisen, the pseudo-sac should be excised. OPENING A LACHRYMAL ABSCESS =Indications.= Lachrymal abscess is due to an inflammation around the sac-wall through which infection of the cellular tissue has taken place. The abscess should not be opened until pus is present, as even considerable swelling and œdema will often subside without suppuration; this is usually about the end of the third day. Further, if the opening be made too soon, the inflammation takes considerably longer to subside. =Instruments.= Beer’s knife, forceps, and probe. =Operation.= Usually performed under gas. An incision is made over the lachrymal sac and is carried downwards and inwards to the bone by a single puncture of the knife. The pus is evacuated, and the cavity stuffed with gauze, which should be changed daily for the first three days. Hot fomentations should be applied. As soon as the swelling has subsided, the lachrymal obstruction should be treated by one of the methods previously described. OPERATIONS UPON THE LACHRYMAL GLAND REMOVAL OF THE PALPEBRAL PORTION =Indications.= For obstinate epiphora after removal of the lachrymal sac. =Instruments.= Fixation forceps (two pairs), two sharp hooks, strabismus scissors, suture. [Illustration: FIG. 170. EXCISION OF THE PALPEBRAL PORTION OF THE LACHRYMAL GLAND. The lid is doubly everted and the gland is dissected out from within outwards.] =Operation.= Usually performed under adrenalin and cocaine. _First step._ The upper lid is doubly everted. The eversion is best carried out by holding the singly everted lid between forceps and then re-everting it; the forceps are then given to an assistant to hold. With a syringe a few drops of 5% cocaine are injected through the conjunctiva into the area to be operated upon. _Second step._ The gland is seen beneath the conjunctiva at the outer part of the upper fornix, seized with forceps, and drawn forwards. A horizontal incision is made with scissors through the conjunctiva, which is dissected backwards. The edges of the wound are then held apart by means of sharp hooks (Fig. 170). _Third step._ The gland, which is seen as a nodule, is drawn forward with forceps. By means of the scissors the gland is separated from its attachments along its whole length, starting on the inner side, the wound being subsequently closed with a few points of catgut suture. REMOVAL OF THE ORBITAL PORTION =Indications.= It is usually undertaken for tumours (endotheliomata, &c.) and retention cysts.