Weight, men 1360 gm.; women 1220 gm. To displace the scalp an incision is carried over the vertex from the tip of one mastoid process to the tip of the other. This should be made from within outward, as by so doing the hair will be divided but not cut. The periosteum should be cut through and the two flaps dissected free. The anterior one extending nearly to the orbits, the posterior is carried backward to the occipital protuberance. * The temporal muscle should be left, but is divided at the point where the cut of the saw is to be made.

The line of opening the skull extends from a point just behind and above the ear, forward over the frontal eminences to a corresponding point on the opposite side. By carrying this line posteriorly over the occipital protuberance the path of the incision is marked out. The incision is started over the forehead and carried backward over the line mapped out. By bracing the saw with the thumb of the left hand and drawing backward a correct start can be made. Continue the incision, first on one side and then on the other, till the mastoid processes have been reached. Care should be taken not to injure the dura. Is often best not to cut through the inner plate of the skull but to break it with a chisel. A posterior incision is continued backward a little above the occipital protuberance.

It should be noted that there are four points where the skull is particularly thick and two where it is very thin. The thick points are over the mastoid processes and in the median line anteriorly and posteriorly. The thin points are over the temporal fossae, where the skull is so thin that a few blows with a chisel will complete the separation.

By inserting the end of a chisel in the mid-line anteriorly and then twisting it the calvarium will be loosened sufficiently to allow the inserting of a hook. By pulling, the skull-cap will be freed unless there are dense adhesions between it and the dura. It is sometimes necessary to remove the calvarium together with the dura.

To remove the dura insert a small knife and cut from within outward along the line of the saw incision. Reflect the two flaps along the mid-line and examine the surface of the brain. The convolutions should be round and not flat. The dura is freed from its attachment to the crista galli and dissected backward. It is separated from the pacchionian bodies, to which it is adherent, by means of slight cuts. The membrane should be examined carefully and the longitudinal sinus opened. The dura should not be cut through posteriorly but should hang down.

The pia is now exposed and the external appearances of the brain should be noted; the degree of congestion, the presence of edema, of tubercles, purulent collections and local or general thickening.

The brain is removed by gently elevating the frontal lobes until the optic nerves are seen. Care should be taken not to cut the olfactory nerves. The optic nerves are cut as far forward as possible, then the carotids are severed.

The tentorium is cut by a sawing motion close to its attachment to the petrous portion of the temporal bone. The various cranial nerves are then divided.

The spinal cord is severed by inserting the scalpel as far as possible into the spinal canal and cutting through with an oblique incision from one side to the other. At the same time the vertebral arteries are cut.

The brain during this should be supported by the left hand.

The base of the skull should be examined, and if a fracture is suspected the dura is stripped off.

To examine the brain place it on its vertex with cerebellum toward one. The pia and the cranial nerves should be examined. Then carefully note the arteries for changes in size, malformations, presence of atheroma, aneurysms, or of tubercles. Separate the Sylvian fissure and examine the vessels there as tubercles, emboli, aneurysms, and hemorrhage may be discovered although absent elsewhere.

To section the brain the following method is generally employed: The brain is placed on its base and the hemispheres separated till the corpus callosum is exposed. The first incision is made into the lateral ventricle about 3 mm. from the median line of the corpus callosum and extending into the anterior and posterior cornua. Posteriorly the convolutions over the cornua are cut through. A series of incisions are made through the hemisphere just external to the basal ganglia with their edges coinciding but going at an angle of about 45 degrees. This gives a number of wedge-shaped portions, held together by the pia, which should not have been removed.

The brain is turned half around and the process repeated on the other side. Care must be taken not to injure the ganglia when opening the ventricle.

The corpus callosum is gently lifted and divided by passing a knife through the foramen of Monro and cutting from below upward. The cut portions are reflected, exposing the velum interpositum and the choroid plexus. The third ventricle is disclosed by drawing back the velum interpositum.

The vermiform process is cut through, opening the fourth ventricle; the aqueduct is cut and all the ventricles are exposed.

The corpora quadrigemina are found by dividing the right posterior pillar of the fornix and reflecting it to the left.

The basal ganglia are exposed by making a series of transverse cuts, the brain being supported from below by the left hand.

The pons and medulla are cut transversely into thin sections.

The cerebellum is divided along the median line into two halves, each of which is subdivided by a series of incisions at right angles to the primary cut.

This method is the one that is employed when the organ has to be examined when fresh. In this way, however, the relations of the different parts may be much disturbed. The best way is to harden the entire brain, either in Müller's fluid or in formaldehyde. When hardened a series of incisions is made transversely through the entire thickness of the organ and extending from one end to the other.

In cutting into the fresh brain the blade of the knife should always be wet so as to prevent its adhering. As long as the pia has not been divided the brain can be restored to its normal form by replacing the wedge-shaped pieces.

The middle ear and the orbits are exposed by breaking through the roof. In removing the eye the anterior half should be left and the space rilled with cotton. The incision is made just posterior to the conjunctival margin and the optic nerve should be removed with it.