wherein the concomitant intellectual activity is reduced to a minimum, _e. g._, in the task of memorizing a poem, or recitation. Here, in the all but complete absence of intellectual activity, the same fatigue results as that induced by a prolonged period of analytic study or investigation, in which imaginative activity and rational thinking are concomitant. The point to be noted, in this latter case, is that the intellect does not show the same dependence upon the physiological vicissitudes as the imagination. The imagery of our imagination, being rigidly correlated with the metabolic processes of waste and repair at work in the cerebral cortex, manifests correspondingly variable degrees of intensity and integrity, but the intensity of thought is not dependent upon this alternation of excitation and inhibition in the cortex. Hence, while the concomitant imagery is fitful, sporadic, and fragmentary, intellectual thought itself is steady, lucid, and continuous. The intensity of thought does not vary with the fluctuations of neural metabolism, and may reach a maximum without involving corresponding fatigue in the brain. The brain-fag, therefore, which results from study does not correspond to the height of our intellectual vision, but is due to the intensity of the concomitant imaginative process. The intellect, therefore, is not subject to the metabolic laws which rigidly regulate organic functions like sense-perception and imagination. Man’s capacity for logical thought is frequently unaffected by the decline of the organism which sets in after maturity. All organic functions, however, such as sight, hearing, sense-memory, are impaired in exact proportion to the deterioration of the organism, which is the inevitable sequel of old age. The intellectual powers, on the contrary, remain unimpaired, so long as the cortex is sound enough to furnish the required minimum of imagery, upon which intellectual activity is objectively dependent. There are, in fact, many cases on record where men have remained perfectly sane and rational, despite the fact that notable portions of the cerebral cortex had been destroyed by accident or disease (_e. g._, tumors). Intellectual thought, therefore, is a superorganic function, having its source in a spiritual principle and not in a corruptible organ.