As everyone knows, it takes a soldier a very long time to learn his drill -- to put himself, for instance, into the attitude of "attention" at the instant the word of command is heard. But, after a time, the sound of the word gives rise to the act, whether the soldier be thinking of it or not. There is a story, which is credible enough, though it may not be true, of a practical joker, who, seeing a discharged veteran carrying home his dinner, suddenly called out "Attention!" whereupon the man instantly brought his hands down, and lost his mutton and potatoes in the gutter. The drill had been gone through, and its effects had become embodied in the man's nervous structure.
The possibility of all education (of which military drill is only one particular form) is based upon the existence of this power which the nervous system possesses, of organizing conscious actions into more or less unconscious, or reflex, operations. It may be laid down as a rule, that if any two mental states be called up together, or in succession, with due frequency and vividness, the subsequent production of the one of them will suffice to call up the other, and that whether we desire it or not.
The body of the accomplished man has thus become by training different from what it once was, and different from that of the rude man; it is charged with stored virtue and acquired faculty which come away from it unconsciously.
The way in which an acquired faculty of the parent animal is sometimes distinctly transmitted to the progeny as a heritage, instinct, or innate endowment, furnishes a striking confirmation of the foregoing observations. Power that has been laboriously acquired and stored up as statical in one generation manifestly in such case becomes the inborn faculty of the next; and the development takes place in accordance with that law of increasing speciality and complexity of adaptation to external nature which is traceable through the animal kingdom; or, in other words, that law, of progress from the general to the special in development which the appearance of nerve force amongst natural forces and the complexity of the nervous system of man both illustrate.
As the vital force gathers up, as it were, into itself inferior forces, it might be said to be a development of them, or, as in the appearance of nerve force, simpler and more general forces are gathered up and concentrated in a more special and complex mode of energy. So again a further specialization takes place in the development of the nervous system, whether watched through generations or through individual life. It is not by limiting our observations to the life of the individual, however, who is but a link in the chain of organic beings connecting the past with the future, that we shall come at the full truth; the present individual is the inevitable consequence of his antecedents in the past, and in the examination of these alone do we arrive at the adequate explanation of him.
