1. EXCISION OF THE UPPER JAW.--With regard to the morbid conditions for which this operation is undertaken, it may be sufficient here to observe, that in no case can the operation be called justifiable in which the disease extends beyond the upper jaw-bone and the corresponding palate-bone, for unless the morbid growth be entirely removed, recurrence is inevitable, and no advantage is gained by the operation. It is undertaken for the removal of tumours of the antrum and of the alveolar margins, in all which cases the section for its removal must be made through healthy bone, and wide of the disease, so as to insure that the whole is removed. There are other cases in which the whole or part of the upper jaw has been removed for the purpose of giving access to disease behind, for example, to naso-pharyngeal polypi with extensive attachments. In describing the operation for the excision of the entire upper jaw, we have to consider--(1.) what incisions through the soft parts will expose the tumour best, and with least deformity; (2.) what bony processes require to be divided, and where. Very various incisions have been recommended by various authors; some describing three, in various directions, forming flaps of different sizes, while others, again, are satisfied with a very small division of the upper lip into the nose, or even attempt removal of the bone without any incision through the skin at all. These discrepancies depend in great measure on different views of what constitutes excision of the upper jaw, the more complicated ones contemplating removal of the whole bone anatomically so called, including the floor of the orbit, while the less complicated ones are suitable for cases in which a much less extensive removal is required. To remove the whole bone, an incision (Fig. XXVII. A) of the skin must extend from the angle of the mouth upwards and outwards in a slightly curved direction with its convexity downwards, as far on the malar bone as half an inch outside of the outer angle of the eye. The flaps must then be raised in both directions, the inner one specially dissected off the bones, so as to expose thoroughly the nasal cavity. It is of great importance thoroughly to display the floor of the orbit, so that the attachment of the orbital fascia may be accurately cut through, the inferior oblique muscle divided at its origin, and the eye and the fat of the orbit cautiously raised from its floor. [Illustration: FIG. XXVII.[107]] Three processes of bone then require attention and division. (1.) The articulation with the opposite bone in the hard palate. To divide this, one incisor tooth at least must be drawn, the soft palate divided by a knife to prevent laceration, and the thick alveolar portion sawn through in a longitudinal direction from before backwards.