About the fourth decade of the nineteenth century, a change came over the general spirit of American society. Historians have often noted the fact and they have described it and explained it in various ways. It was a time of storm and stress, a period of controversy and conflict and finally war. There was scarcely a single phase of life that was not infected. As if by some preconcerted signal the souls of men in most diverse groups and relationships suddenly became sensitive and combative. The result was one of those swift ruptures with the past that leave abiding scars in the body of society.