greater, the whole head is distended, the forehead projects outwards, the eyes are fixed and shed tears frequently. In these cases we reprobate any surgical interference, although some remove a piece of the bone by trepanning, as will be described in the section on fractures of the bones of the head. But if the fluid be formed between the skin and the pericranium, and the swelling be small, we may make one transverse incision through the middle. But if the fluid is seated between the pericranium and the bone, and the tumour is large, we make two incisions intersecting one another in the middle; or if it is still larger we may make three imitating the form of the Greek letter Η. After the operation, having evacuated the fluid and applied suitable compresses, we bind it up, and soak it with wine and oil until the third day; after which, having loosed the bandages, we may cure it by the application of pledgets; or, if the bone is long of incarnating we may scrape it lightly. * * * * * COMMENTARY. See Hippocrates (de Morbis, ii, 15); Celsus (iv, 2); Aëtius (vi, 1); Galeni (ut aiunt) Isagoge; Antyllus (apud Nicetam); Avicenna (iii, 1; iv, 2); Avenzoar (I, 9, 17); Albucasis (Chirurg. ii, 1); Haly Abbas (Pract. ix, 16); Rhases (Contin. xxvii; and ad Mansor. ii, 25.) Hippocrates gives an interesting account of water in the brain, the symptoms of which, as described by him, are pain in the opening of the head and temples, rigor, fever, double vision, impatience of sounds, vomiting of phlegm, &c. He recommends emetics, caputpurgia, and afterwards purgatives. He also makes mention of hellebore and sternutatories, and even directs us to perforate the skull, or, in other words, to trephine it. Celsus describes only the hydrocephalus externus. He recommends us to use stimulant applications to the head, such as sinapisms, and if this treatment does not succeed, he directs us to use the scalpel. The case, otherwise, is to be treated like dropsy, with sudorifics, exercise, friction, and diuretics. Our author’s description is mostly abridged from Aëtius, who gives an extract from Leonidas. Even when the fluid is collected within the skull he directs us to let it out, provided it is in such quantity as to occasion a separation of the suture. The account of the disease, given by Antyllus, in the Collection of Nicetas is nearly the same as our author’s. He speaks favorably of the operation only in cases in which the water is collected externally to the bone. In the ‘Isagoge,’ generally ascribed to Galen, it is directed, when the water is collected below the skin on the pericranium, to evacuate it by making two or three straight incisions; and when immediately below the bone, to perforate it; but the case in which the fluid is seated between the membrane and the brain is pronounced to be utterly incurable.