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production of vomiting," We think the more correct statement would have been, the mere idea of a nauseous taste can produce vomiting. In this form, it loses all pertinence as proof. The active results follow from the idea, the action in the brain, and not from the sensation. We do not in such cases suppose that we taste the disgusting food, but only that we conceive its taste. "The mere sight of a person about to pass a sharp instrument over glass or porcelain, is sufficient, as Darwin remarks, to excite the well known sensation in the teeth."

Now the setting of the teeth on edge, is an effect of nervous action, and may as fitly follow that action when coming in connection with the imagination, as when occasioned by the senses. The fact that fancy affects the nervous system, and hence the muscular system, in a manner allied to that of the senses, no more proves the identity of imagination and sensation than a fright at a ghost proves the existence of a ghost. These examples do not reach deep enough to do the work required of them. They only show the results to be in a measure the same, whether the object be imagined or perceived, whether the initiative is from within or from without: whereas, they ought to show the organs of sense so affected in what we call imagination as to be a sufficient cause of the effects which follow. Against this, mental and physical experience testifies. (1) We distinguish easily between acts of imagination and perception, both in the character and locality of the activity. An impression that lingers in the organ, or renews itself there, implies disease. The organ shows its power by a quick, exact response to external conditions only. (2) We observe, also, that the action occasioned by the images of fancy in most men is slight and ineffectual when contrasted with the results of real perception. Great diversities in character hinge just here, on the predominance of the senses