It is evident that if we assume Darwin’s theory of descent in sociology we must look for the beginnings of many peculiarly human things in the animal world below man. Human institutions, according to this theory, could not be supposed to have an independent origin, or human society in any of its forms to be a fact by itself, but rather all human things are connected with the whole world of animal life below man. Thus if we are, according to this theory, to look for the origin of the family, we should have to turn first of all to the habits of animals nearest man.