When the tumour is large, the skin incision should be as free as possible because branches of the facial nerve are very apt to be adherent to the capsule of the growth, especially at the deeper part, and it is essential therefore to see exactly what is being done during removal of the tumour. When the growth is situated low down, a curved incision over the lower part of the parotid gland running forwards to the jaw will generally give good access. The skin and subcutaneous tissue are dissected up, but care must be taken to avoid injuring the branches of the facial nerve as the incision is deepened. The parotid tissue over the growth is torn through where it is thinnest; indeed, in many cases the tumour is found uncovered by gland tissue. The capsule of the tumour is thus exposed and its separation from the parotid is effected with a blunt dissector until the growth can be pulled or pushed out of its bed and its deeper connections separated. It is at the deeper part that the branches of the facial nerve are most likely to be met with.

The hæmorrhage is usually unimportant unless a vein is torn in separating the deeper parts. In that case an attempt should be made to seize and tie the bleeding point, but if this fails, it may be better to plug the wound for twenty-four hours and stitch it up afterwards rather than to enlarge the opening in the gland tissue.

MALIGNANT TUMOURS.

Malignant disease of the parotid may arise primarily in the gland or develop in a 'parotid tumour and ultimately involve the gland. It may also occur secondarily from the development of cancerous glands. in the substance of the parotid or from the spread of malignant disease by direct continuity from carcinoma of the ear or the skin.

TREATMENT.-If an operation is to be performed at all, it must be complete removal of the parotid gland, and although this is not worth while in the majority of cases, it may be done when the disease is fairly limited and after any primary focus elsewhere has been completely eradicated. The operation must, of course, involve facial paralysis; any attempt to preserve the nerve will almost certainly end in recurrence of the disease.

Excision of the Parotid Gland. As a preliminary step, a loop of silk should be passed round the external carotid artery at its origin (see Vol. II. p. 204). This can be pulled on gently during the operation if necessary, so as to control the bleeding temporarily; the thread can be removed at the end of the operation. The shoulders should be raised and the head turned to the opposite side and allowed to fall back.

When the skin is not involved, a curved incision is made commencing above at the junction of the zygoma with the malar bone, extending along the zygoma to the front of the ear, curving downwards behind and parallel to the ascending ramus of the jaw, and finally turning forwards

again over the angle as far as the anterior border of the masseter. This flap of skin and fat must be turned forwards over the face. If the gland extends downwards into the neck to any extent, it is well to add an incision along the anterior border of the sterno-mastoid muscle. The lower and posterior part of the gland should then be lifted gradually from its bed. This can usually be done by dividing the deep fascia at the anterior border of the sterno-mastoid, gradually separating the tissues with the handle of the knife and pulling the gland forwards. After a time the external carotid artery is exposed as it passes beneath the gland, and this vessel should be clamped and divided. The facial nerve enters at the posterior margin and divides into two main branches, the temporo-facial and the cervico-facial, and should be saved as long as possible, but it is usually out of the question to retain any part ultimately. The deeper lobules of the gland which pass between the mastoid process and the ramus of the jaw and between the internal and external pterygoid muscles are best enucleated with a dissector, great care being taken to avoid injury to veins which might be a source of very considerable difficulty and danger. The shelling-out of the deeper part of the gland is facilitated by pulling the jaw as far forwards as possible. The anterior part of the gland is superficial and is readily removed. The divided end of Stenson's duct should be ligatured with catgut, the bleeding points secured, and the wound stitched up, a drainage tube being inserted at the lower angle.

When the skin is implicated, a wide area must be taken away, and it will be necessary to turn in flaps from the neck to fill the gap.