As early as 1842, in a series of letters to the Nonconformist newspaper on "The Proper Sphere of Government," he propounded a belief in human progress based on the modifiability of human nature through adaptation to its social surroundings, and he asserted the tendency of these social arrangements to assume of themselves a condition of stable equilibrium.

Properties of Nervous Tissue Impressibility, Conductivity, Modifiability.

The third property of nerve-cells which is important in study is modifiability.

The nervous system, however, possesses the power of modifiability to a marked degree, even a single impression sufficing to make striking modification.

There is a comforting thought, however, which is derived from the factor of modifiability, in that with each succeeding repetition, the task becomes easier, because the path becomes worn smoothly and the nervous current seeks it of its own accord; in other words, each act and each thought tends to become habitualized.

In nerve tissue, impressibility, conductivity and modifiability are developed to a marked degree.

This trait of nerve modifiability is one factor which accounts for greater retentive power in some persons than in others.