=Their Solution.=--The forgotten thing is felt by us as a gap in the midst of certain other things. We possess a dim idea of where we were and what we were about when it last occurred to us. We recollect the general subject to which it pertains. But all these details refuse to shoot together into a solid whole, for the lack of the missing thing, so we keep running over them in our mind, dissatisfied, craving something more. From each detail there radiate lines of association forming so many tentative guesses. Many of these are immediately seen to be irrelevant, are therefore void of interest, and lapse immediately from consciousness. Others are associated with the other details present, and with the missing thought as well. When _these_ surge up, we have a peculiar feeling that we are 'warm,' as the children say when they play hide and seek; and such associates as these we clutch at and keep before the attention. Thus we recollect successively that when we last were considering the matter in question we were at the dinner-table; then that our friend J. D. was there; then that the subject talked about was so and so; finally, that the thought came _à propos_ of a certain anecdote, and then that it had something to do with a French quotation. Now all these added associates _arise independently of the will_, by the spontaneous processes we know so well. _All that the will does is to emphasize and linger over those which seem pertinent, and ignore the rest._ Through this hovering of the attention in the neighborhood of the desired object, the accumulation of associates becomes so great that the combined tensions of their neural processes break through the bar, and the nervous wave pours into the tract which has so long been awaiting its advent. And as the expectant, sub-conscious itching, so to speak, bursts into the fulness of vivid feeling, the mind finds an inexpressible relief. [Illustration: FIG. 61.] The whole process can be rudely symbolized in a diagram. Call the forgotten thing _Z_, the first facts with which we felt it was related _a_, _b_, and _c_, and the details finally operative in calling it up _l_, _m_, and _n_. Each circle will then stand for the brain-process principally concerned in the thought of the fact lettered within it. The activity in _Z_ will at first be a mere tension; but as the activities in _a_, _b_, and _c_ little by little irradiate into _l_, _m_, and _n_, and as _all_ these processes are somehow connected with _Z_, their combined irradiations upon _Z_, represented by the centripetal arrows, succeed in rousing _Z_ also to full activity.