The calvarium having been removed, and the superior longitudinal sinus opened, and the condition of its contents noted, the dura mater, after its careful examination, may be cut through with the knife or scissors in the line of the division of the bone. The membrane may now be lifted up, when adhesions will be found between its under surface and the pia mater, along either side of the falx cerebri. These should not be mistaken for results of inflammation, as they sometimes are, they being simply the points of entrance of the veins of the pia mater into the superior longitudinal sinus. These having been divided, with the falx near its attachment to the crista galli, the whole may be turned back, exposing the brain. To remove the latter, take away the block from beneath the head, and lifting the anterior lobes of the brain, divide successively the several pairs of nerves as they appear in sight, with also the tentorium on either side, and as the brain falls back into the left hand, the knife may be passed down into the foramen magnum, and the medulla oblongata and vertebral arteries divided, when the whole may be lifted from its position. More or less blood with the _cerebro-spinal fluid_ will necessarily flow off during this operation, to secure which, a bucket should be placed beneath the edge of the table, over which the head should slightly project. In dropsy of the brain, although the fluid is mainly in the ventricles, it may escape during the operation and be caught in the same manner. The external surface of the brain having been carefully examined, the hemispheres may be sliced off to a level with the corpus callosum, when, by removing the latter, the cavities of the lateral ventricles will be exposed. After a careful inspection of the several objects seen here, the fornix and velum interpositum may be removed, opening thus into the third ventricle. Slices may now be taken off the corpora striata and optic thalami, with deeper portions of the hemispheres, and sections made of the crura cerebri cerebellum and medulla oblongata, thus giving an opportunity of judging of the condition of all those parts. After the removal and examination of the brain, attention should be given to the _base of the skull_. The lateral and other sinuses should be laid open, the dura mater, as far as possible, torn away, and the bones examined for fractures, caries, abnormal growths, etc.