(2) In more severe cases there are often several _visible areas of extravasation_, most commonly in the grey matter of the cortex (Fig. 184). These foci vary in size from a split-pea to a hazel-nut, and consist of a dark central zone of extravasated blood, surrounded by an area of "red softening" of the brain matter, beyond which are numerous minute capillary hæmorrhages. These intra-cerebral lesions may be accompanied by an effusion of blood into the meshes of the arachno-pial membrane, and they may occur either at the part of the head struck, or at the opposite pole of the axis of percussion--the so-called point of _contre-coup_. The symptoms vary with the size and site of the extravasations. It is probable that the phenomena of "cerebral irritation" are to be explained by the occurrence of such hæmorrhages widely scattered through the cerebral cortex. Effusions into the cortical motor areas give rise to irritation or paralysis of the muscles governed by the affected centres. Different forms of aphasia and interference with vision or with hearing follow implication of the centres governing these functions. In the pre-frontal and in the lower temporal convolutions no special symptoms seem to follow. When the hæmorrhages are extensive and numerous, symptoms of compression may ensue, and these are aggravated when œdema of the brain is superadded. Localised hæmorrhages also occur, although less frequently, in the crura cerebri, the pons, the floor of the fourth ventricle, and the cerebellum. In these situations they usually prove fatal by causing rapidly advancing coma and interference with the respiratory and cardiac centres. The temperature immediately rises to 106° or even 108° F., and a modified form of Cheyne-Stokes respiration is present. (3) Still more gross lesions, in the form of distinct _lacerations_, are comparatively common at the tips of the frontal, temporal, and occipital lobes, on the surface of the cerebellum, and at the base of the brain. These are usually associated with symptoms of compression in its most typical form, and as a rule prove fatal. The grey matter is torn, and extensive effusion of blood takes place into the brain substance, and on the surface, filling up the sulci, and distending the arachno-pial space (Fig. 184). In a compound fracture, brain matter may be extruded through the opening in the skull. (4) The extravasated blood may burst _into the lateral ventricles_, in which case the pulse becomes small and rapid--130, 160, or even 170. The respiration also is rapid--45 to 60--and greatly embarrassed, and the temperature suddenly rises to 103° or 104° F., and continues to rise till death ensues.