points, and, what is more significant, there is now unanimity among the specialists as regards functional limitation. Interesting as many of the details might be, it is impossible to give even a summary of them in this essay. It is sufficient for our purpose to show the bearing of the facts of localization of function upon the problem of psychogenesis. The first proposition derived from these facts is, that psychosis and neurosis are phenomena having common space-relations. The second is, that they are manifested in distinct tracts of organic tissue and are, therefore, not only correlated generally but specifically in the organism. The third inference is, that these specifically correlated psychoses and neuroses result from a differentiation of function that accompanies a differentiation of the tissue in which they have their seat; or, in other words, that, as parts of the brain are developed and adapted to specific uses, the correlated psychic manifestations, although not identical either with their substance or their activities, are also developed and adapted in a corresponding manner.
Unconscious Cerebration.
While it may be said that every psychosis is accompanied by a correlated neurosis, it cannot be maintained that every neural change is attended with consciousness. The nutritive processes in the tissues of the brain during sleep have no mental concomitants. Other changes of a more complex character are also unattended with conscious phenomena. Unconscious cerebration occurs in which very complicated acts, including those, perhaps, of ideation, are perfectly performed. It is now established that the paths of reflex action, traversed by external stimuli reappearing as motions, are continuous; that is, that the afferent nerves terminate in ganglia whence originate the efferent nerves by which the muscles are set in motion. This statement is subject, however, to the qualification that no nerve seems to be strictly continuous, but to consist in a series of elements through which motion has continuity. The in-carrying and out-carrying tracts of nerves are woven into a complex
