Accepting this view as on the whole well founded, I shall speak of an ideational, or rather an imaginational; and a sensational nervous process, and not of an ideational and a sensational centre.[12] The special force that belongs to the representative element in a percept, as compared with that of a pure "perceptional" image,[13] is probably connected with the fact that, in the case of actual perception, the nervous process underlying the act of imaginative construction is organically united to the initial sensational process, of which indeed it may be regarded as a continuation.
For the physical counterpart of the two stages in the interpretative part of perception, distinguished as the passive stage of preperception, and the active stage of perception proper, we may, in the absence of certain knowledge, fall back on the hypothesis put forward by Dr.J.
Hughlings Jackson, in the articles in _Brain_ already referred to, namely, that the former answers to an action of the right hemisphere of the brain, the latter to a subsequent action of the left hemisphere.

The expediting of the process of preperception in those cases where it has frequently been performed before, is clearly an illustration of the organic law that every function is improved by exercise.

And the temporary disposition to perform the process due to recent imaginative activity, is explained at once on the physical side by the supposition that an actual perception and a perceptional image involve the activity of the same nervous tracts.

For, assuming this to be the case, it follows, from a well-known organic law, that a recent excitation would leave a temporary disposition in these particular structures to resume that particular mode of activity.
What has here been said about visual perception will apply, _mutatis mutandis_, to other kinds.

Although the eye is the organ of perception _par excellence_, our other senses are also avenues by which we intuit and recognize objects.