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.
