In the chapter on Imagination we shall return to these differences in the sensory spheres of different individuals. Meanwhile few things show more beautifully than the history of our knowledge of aphasia how the sagacity and patience of many banded workers are in time certain to analyze the darkest confusion into an orderly display. There is no 'organ' of Speech in the brain any more than there is a 'faculty' of Speech in the mind. The entire mind and the entire brain are more or less at work in a man who uses language. The subjoined diagram, from Ross, shows the four parts most vitally concerned, and, in the light of our text, needs no farther explanation (see Fig. 48, p. 117). [Illustration: FIG. 47.] =Centres for Smell, Taste, and Touch.=--The other sensory centres are less definitely made out. Of smell and taste I will say nothing; and of muscular and cutaneous feeling only this, that it seems most probably seated in the motor zone, and possibly in the convolutions immediately backwards and midwards thereof. The incoming tactile currents must enter the cells of this region by one set of fibres, and the discharges leave them by another, but of these [Illustration: FIG. 48.--_A_ is the auditory centre, _V_ the visual, _W_ the writing, and _E_ that for speech.] =Conclusion.=--We thus see the postulate of Meynert and Jackson, with which we started on p. 105, to be on the whole most satisfactorily corroborated by objective research. _The highest centres do probably contain nothing but arrangements for representing impressions and movements, and other arrangements for coupling the activity of these arrangements together._ Currents pouring in from the sense-organs first excite some arrangements, which in turn excite others, until at last a discharge downwards of some sort occurs. When this is once clearly grasped there remains little ground for asking whether the motor zone is exclusively motor, or sensitive as well. The whole cortex, inasmuch as currents run through it, is both. All the currents probably have feelings going with them, and sooner or later bring movements about. In one aspect, then, every centre is afferent, in another efferent, even the motor cells of the spinal cord having these two aspects inseparably conjoined. Marique, and Exner and Paneth have shown that by cutting _round_ a 'motor' centre and so separating it from the influence of the rest of the cortex, the same disorders are produced as by cutting it out, so that it is really just what I called it, only the funnel through which the stream of innervation, starting from elsewhere, escapes; _consciousness accompanying the stream, and being mainly of things seen if the stream is strongest occipitally, of things heard if it is strongest temporally, of things felt, etc., if the stream occupies most intensely the 'motor zone.'_ It seems to me that some broad and vague formulation like this is as much as we can safely venture on in the