In the present section the writer proposes to deal at length with the symptomatology, which is the psychic equivalent of those physical states of the cerebrum which are the necessary precursors of dissolution of the cerebral neurones. There being no suitable word in use for the description of this symptomatology, and it not appearing desirable to coin a new one for the purpose, the term “mental confusion” will be employed to connote, in the broadest sense, the mental symptoms which occur in association with certain pathological states of the cortical neurones which may be followed by the recovery or by a more or less extensive dissolution of these elements.