Morell says: “We have every reason to believe that mental power when once called forth follows the analogy of everything we see in the material universe in the fact of its perpetuity. Every single effort of mind is a creation which can never go back again into nonentity. It may slumber in the depths of forgetfulness as light and heat slumber in the coal seams, but there it is, ready at the bidding of some appropriate stimulus to come again out of the darkness into the light of consciousness.” Beattie says: “That which has been long forgotten, nay, that which we have often in vain endeavored to recollect, will sometimes without an effort of ours occur to us on a sudden, and, if I may so speak, of its own accord.” Hamilton says: “The mind frequently contains whole systems of knowledge which, though in our normal state they may have faded into absolute oblivion, may in certain abnormal states, as madness, delirium, somnambulism, catalepsy, etc., flash out into luminous consciousness. . . . For example, there are cases in which the extinct memory of whole languages were suddenly re-
