Thus the movements of commerce have introduced fresh and vigorous blood into various parts of England: the new-comers have intermarried with the residents, and their characteristics have been prepotent in the descendants of the mixed marriages.

It is easy to specify families who are characterised by strong resemblances, and whose features and character are usually prepotent over those of their wives or husbands in their joint offspring, and who are at the same time as prolific as the average of their class.