Now of all possible agencies that may bring these predispositions into play—­that may awaken our ancestral memories, if you choose to adopt this theory—­I submit that the book stands at the very head.  For it is itself a racial record; it may contain, in the form best suited to awaken our predispositions, the very material which, long ages ago, was instrumental in handing those predispositions down to us.  It is in tune with our latent memories, and it may set them vibrating more vigorously than any merely contemporary agency.

Does this not place in a new and interesting light the library and the books of which it is composed?  We have learned to respect them as the records of the race and to recognize their value as teachers and their power as energizers; in addition we now see that they may act as fingers on invisible mental triggers.  A slight impulse—­altogether trivial compared with its effect—­and off goes the gun.  The discharge may carry a line to a wrecked ship, or it may sink her with all on board.

We frequently hear it said of some book whose tendency is bad:  “Well, it can’t hurt me, anyway; I’m immune.”  Are you quite sure?  Have you gone quite to the bottom of those ancestral memories of yours, and are you certain that there are none that such a book may rouse, to your harm?

On the other hand, does this not explain much that has always interested the librarian; for instance, the vast popularity of fairy tales, especially those that date back to our racial infancy?  I need dwell no further on the economic importance of the book as viewed from this standpoint.

But it has also a function almost diametrically opposed to that which we have just considered; besides harking back to what is oldest it looks forward to what is newest.  It may stir us by awakening dim racial recollections; but it may also thrill us by adding to the store of what is already in the mind.  In fact, we like to assimilate new ideas, to think new thoughts, to do new acts; we like to read or hear something that we could not have produced ourselves.  When we are young and ignorant, therefore, we like music or art or literature that appears trivial to us as we grow older and have developed our own creative powers.  A poem that is no better than one a man might dash off himself he likes no longer; he prefers to be confronted with something that is above and beyond his own powers, though not above his comprehension.  Thus, as he grows, his zone of enjoyment shifts upward, and the library covers the whole moving field.  When Solomon John Peterkin, pen in hand, sat down to write a book, he discovered that he hadn’t anything to say.  Happy lad!  He had before him all literature as a field of enjoyment, for all, apparently, was beyond his creative efforts.