EVOLUTION is the working hypothesis of most scientific men at the present time. In no branch of science is it without influence, and in the sciences which deal with life it is dominant. We cannot escape from it. Its technical phrases have become parts of current common speech; and such words as “natural selection,” the “struggle for existence,” and “the survival of the fittest” are on the lips of every one. It does not matter to what sphere of human work we turn, for in all alike we meet with the same mental atmosphere. Are we students of physics or chemistry, we have no sooner mastered the elements of the science than we are plunged into questions which deal with the “evolution” of the “atom” or the “molecule” from simpler forms of matter. Do we study mechanics, then we are brought into a sphere where men talk of the evolution of the steam engine or of some other machine which has slowly grown from less to more till it has reached its present state. Are we students of man, then we become accustomed to inquiries into the evolution of the family, of marriage, of the community, of the state. Morality is evolved, religion also.