objective words and phrases and thoughts of his own brain, which, perhaps, have long been parts of his mental possessions, rise up like ghosts in the midst of his narration, throw aside the original words and phrases and thoughts, and take their places so perfectly and so harmoniously that the intrusion is not suspected.
It may be said—indeed, it is often said—that memory is a distinct and narrow faculty, in no way correlated to other and more important faculties, and that its perfectness or imperfectness has little relation to the cerebral force. Even if this view of the nature of memory were the correct one, it would not invalidate what is here claimed of the relation of memory to human testimony. But this theory of the nature and office of memory is not the correct one; it is opposed to all that is known of the brain and of its functions, whether studied physiologically or psychologically. Memory is simply a register of a small fraction of the impressions made on the brain; there are, therefore, as many different kinds of memory as there are different faculties or combinations of faculties. Memory is a measure of mind; but, as there are as many varieties of memory as there are varieties of talents in man, the memory of any man can only measure the talent peculiar to himself. We remember what we have a capacity to comprehend. Any man, it has been said, is willing to admit that his memory is poor, but no one will admit that his judgment is poor; and yet judgment is largely the result of memory. One may have a good judgment in some departments, but a very poor judgment in other departments; but, in those departments in which the judgment is good, the memory must also be good.
The relation of memory to mind is illustrated, if not demonstrated, in the early and late history of infant prodigies, such as blind Tom the musician, Colburn the mathematician, and the famous "boy orator." An analysis of the mental powers of any of these prodigies brings out these four facts common to them all: 1. Extraordinary memory in some one department; 2. Correspondingly extraordinary genius in that department; 3. Marked and unusual deficiency of other mental qualities, amounting in some instances to idiocy; 4. Decline of their special gifts corresponding to the development of other faculties on reaching maturity. "In monstrosities Nature reveals her secrets;" the physiology of mind, the general relation of mind to brain, and the relation of memory to mind, can all be studied effectively through infant prodigies. In no class of beings are the limitations of the human brain so thoroughly demonstrated as in these very prodigies that are supposed to illustrate in a marvelous way the capacities of intellect: all their special endowments are bestowed at the price of general endowments; the ordinary is sacrificed to the extraordinary. If they ever mature and become well-balanced citizens, the particular genius that made their childhood famous must correspondingly suffer. Even the average child, as we have seen, loses its memory in certain directions as it advances to maturity; hence the common but erroneous belief