Plate I. Dissection of the basal arteries in arteriosclerosis 6 II. Dissection of the cerebral arteries in arteriosclerosis 8 III. The arteries at the base of the brain in advanced calcareous arteriosclerosis 10 IV. A dissection of the sclerotic arteries of the mesial surface and the insula, etc 12 V. Dissection of the cerebral arteries, showing an anomalous circle of Willis, etc 14 VI. Aneurisms of the basal arteries and an anomalous anterior choroid artery of the left side 16 VII. The base of the brain showing arteriosclerosis and anomalous arteries 18 VIII. The base of a brain showing arteriosclerosis 20 IX. The base of the brain showing arteriosclerosis of the small vessel type 22 X. The base of a brain showing arteriosclerosis 24 XI. Dissection showing the distribution of the anterior cerebral arteries and the distribution of a large median anterior cerebral artery XII. A large arteriosclerotic softening of the left hemisphere 28 XIII. A large arteriosclerotic softening of the left hemisphere 20 XIV. Left half of brain with multiple cortical softenings due to arteriosclerosis 32 XV. The base of the brain showing arteriosclerosis of the basal vessels and softening from obstruc- tion of the right posterior cerebral artery 34 XVI. A horizontal section of a brain showing central softenings from arteriosclerosis 36 XVII. A horizontal section of a brain showing central arteriosclerotic softenings 38 XVIII. A horizontal section of a brain showing syphilitic softenings of the interior and the cortex. . 40 XIX. Horizontal section of a brain showing cicatricial central softenings 42 XX. The superior aspect of the brain in a case of thrombotic softening affecting the whole left hemi- sphere 44 XXI. Arteriosclerotic softenings of cerebrum 46 XXII. A brain the seat of a large hemorrhage causing left hemiplegia XXIII. A horizontal section of a brain showing hemorrhage in the right basal ganglia 50 XXIV. Cerebral hemorrhage destroying the right internal capsule and the nucleus lentiformis 52 XXV. Horizontal section of a brain which had been the seat of a hemorrhage 54 XXVI. Horizontal section of a brain showing the effects of a former hemorrhage 56 XXVII. The left hemisphere in a case of extreme cerebral atrophy 58 XXVIII. The superior surface of a brain from a case of senile dementia with numerous cortical soften- ings due to arteriosclerosis 60 XXIX. Extreme atrophy of frontal regions of the brain 62 XXX. The superior surface of the cerebrum, showing atrophy; the fissures are artificially separated. . . 64 XXXI. The superior surface of a brain in chronic dementia with cerebral atrophy 66 XXXII. The superior aspect of the brain in a case of chronic dementia with atrophy 68 XXXIII. Mesial surface of the right hemiencephalon in chronic melancholia 70 XXXIV. Superior surface of the brain showing arteriosclerotic devastations of the cortex 72 XXXV. A dissection showing the basal arteries and the atrophy of the brain in the region of the insulae. 74 XXXVI. Horizontal section of a brain from a case of senile dementia 76 XXXVII. A horizontal section of a brain of syphilitic dementia 78 XXXVIII. Brain of a case of senile dementia in a patient aged 99 years 80 XXXIX. Lateral surface of the left hemiencephalon in a case of chronic melancholia 82 XL. The superior surface of the brain in chronic mania 84 XLI. The effects of removal of the pia in paresis 86 XLII. The left hemisphere in a case of paresis with flaking of the cortex 88 XLIII. The right hemiencephalon in a case of paresis 90 XLIV. Brain showing chronic internal hydrocephalus 92 XLV. Chronic acquired internal hydrocephalus 94 XLVI. Chronic acquired internal hydrocephalus 96 XLVII. A case of chronic acquired circumscribed internal hydrocephalus XLVIII. Transverse section of the brain showing chronic internal hydrocephalus, probably congenital. 100 XLIX. Horizontal section of a brain from a case of senile dementia with ventricular dilatation 102 L. A case of chronic congenital internal hydrocephalus 104 LI. A case of chronic congenital internal hydrocephalus. Interior of basal portion 106 LII. A case of chronic congenital internal hydrocephalus. Interior of upper portion 108 LIII. Superior surface of a brain showing leptomeningitis 110 LIV. The inferior surface of a brain showing leptomeningitis 112 LV. A brain showing chronic meningeal thickening and atrophy consequent upon bullet wound of the head 114 LVl. The right hemiencephalon from a case of acute mania 116 LVII. The superior aspect of the brain in a case of extreme meningeal hypersemia with chronic oedema 118 LVIII. The superior aspect of a brain from a case of extreme atrophy in the terminal dementia of melancholia 120 LIX. Superior surface of the brain showing engorgement of the pial veins 122 LX. View of the brain in a case of meningo-eneephalitisof childhood, with arrest of development of the brain. Photographed with a brain of normal size and weight 124 LXI. Views of the brain in a case of meningo-encephalitis of childhood, with arrest of development of the brain 126 LXII. The superior surface of a brain compressed by accumulation of subdural fluid 128 LXIII. The superior aspect of a brain showing compression of the left hemisphere by a hsematoma of the dura 130 LXIV. Right hemisphere of a case of atrophic sclerosis in epilepsy 132 LXV. The superior surface of a brain with localized sclerosis of the left frontal lobe 134 LX VI. A case of sclerosis of a portion of the right hemisphere in epilepsy 136 LXVII. Sclerosis of a portion of the right hemisphere in epilepsy 138 LXVIII. Mesial view of the left hemisphere showing absence of the septum pellucidum 140 LXIX. Horizontal section of a brain without a septum pellucidum 142 LXX. Horizontal section of a brain made on a level with the junction of the fornix with the callosum. 144 LXXI. Horizontal section of a brain from a case of dementia prsecox 14 LXXII. Section of brain showing glioma of the left frontal lobe 148 LXXIII. Plate showing a tumor of the dura penetrating the brain 150 LXXIV. Mesial surface of the left hemiencephalon, showing cavity left in the brain after enucleation of the tumor of the dura shown on Plate LXXV. Tumor of the dura penetrating the brain 154