A father wishes to show to some guests the progress of his rather dull child in kindergarten-instruction. Holding the knife upright on the table, he says, "What do you call that, my boy?" "I calls it a _knife_, I does," is the sturdy reply, from which the child cannot be induced to swerve by any alteration in the form of question, until the father, recollecting that in the kindergarten a pencil was used and not a knife, draws a long one from his pocket, holds it in the same way, and then gets the wished-for answer, "I calls it _vertical_." All the concomitants of the kindergarten experience had to recombine their effect before the word 'vertical' could be reawakened. =Total Recall.=--The ideal working of the law of compound association, as Prof. Bain calls it, were it unmodified by any extraneous influence, would be such as to keep the mind in a perpetual treadmill of concrete reminiscences from which no detail could be omitted. Suppose, for example, we begin by thinking of a certain dinner-party. The only thing which all the components of the dinner-party could combine to recall would be the first concrete occurrence which ensued upon it. All the details of this occurrence could in turn only combine to awaken the next following occurrence, and so on. If _a_, _b_, _c_, _d_, _e_, for instance, be the elementary nerve-tracts excited by the last act of the dinner-party, call this act _A_, and _l_, _m_, _n_, _o_, _p_ be those of walking home through the frosty night, which we may call _B_, then the thought of _A_ must awaken that of _B_, because _a_, _b_, _c_, _d_, _e_ will each and all discharge into _l_ through the paths by which their original discharge took place. Similarly they will discharge into _m_, _n_, _o_, and _p_; and these latter tracts will also each reinforce the other's action because, in the experience _B_, they have already vibrated in unison. The lines in Fig. 57 symbolize the summation of discharges into each of the components of _B_, and the consequent strength of the combination of influences by which _B_ in its totality is awakened. [Illustration: FIG. 57.]