I. While arterio-sclerosis of some degree is a commonplace finding in cases of mental disorders, especially in advanced life, there are cases where the cardio-vascular disorder seems to be the central element in the clinical and anatomical picture.II. Certain cases symptomatologically described as melancholia, hypochondria, neurasthenia, etc., may be better grouped on etiological grounds as eases of arterio-sclerotic brain disorder; while the arterio-sclerosis is an important factor, the factors which led to the symptomatological grouping are not to be neglected. This necessitates the analysis of the depressions in advanced life.III. In certain cases of organic dementia the arterio-sclerotic changes are obviously the most important element in the process and the term arterio-sclerotic dementia is justifiable; but the relation of certain mental symptoms to similar ones in the presenile and senile psychoses must be kept in mind. This necessitates the analysis of the presenile and senile psychoses.It is premature to correlate the whole symptomatology with the arterio-sclerotic part of the anatomical findings.IV. The neurological picture in advanced cerebral arterio-sclerosis is still ill-defined; and for the differential diagnosis of the various organic dementias further clinical material is required.V. In certain cases of epilepsy with onset in late life, the convulsions and general symptomatology are closely related to arteriosclerosis.