=Syphilitic Tumors= are occasionally found in the brain, situated near its surface. Their characters are not such as to permit of their ready recognition, except when associated with syphilitic growths in other parts of the body. They may vary in size from a pin’s head to a cherry. They present a rounded or irregular form, a yellow color, and are composed of spindle-shaped or round cells, which may undergo a cheesy degeneration. =Obstruction of Cerebral Arteries.= Patients suffering from endocardial inflammations, or from aneurism of the arch of the aorta, or from any cause having fibrinous deposits forming in the heart, are liable to have the same washed along the carotids, and thus carried into the vessels of the brain, thereby deranging the circulation through this organ. The symptoms resulting, are generally those of apoplexy. Hemiplegia, with or without loss of consciousness, follows. Softening of the cerebral substance follows as a result of the accident, and it is not impossible but that the presence of these bodies is the general cause of this structural change of the brain. The position of the embolus, in fatal cases, is usually in one of the middle cerebral arteries; these vessels being in a more direct line with the internal carotids. They may lodge, however, in the vertebrals or basilar, yet through the circle of Willis, the several parts of the brain will still receive a partial supply of blood. =Atheromatous Degeneration, and Calcification of Cerebral Arteries.= The coats of the arteries of the brain in old people, are liable to become infiltrated with atheromatous and calcareous matter to such a degree, as to render them rigid, and inelastic. While the arteries of the base of the brain, as the basilar, the cerebrals, or the communicating of the circle of Willis, are more liable to this change, it may involve the smaller branches as well. The increased thickness of the coats of the vessels, results in a diminution of the calibre, while they are enlarged in external circumference. Resulting from this state of the vessels, we shall have disturbed circulation, followed by effusion, and in some cases by atrophy of the brain. Attending this condition, are frequent attacks of stupor and insensibility, lasting for several hours or even days. Again, from the weakened condition of the coats of the vessels in these cases, we may have an _aneurism_ resulting, the walls of which suddenly giving away, death from hæmorrhage speedily follows. Section IV. OF THE SPINAL CORD.