ABSTRACT
Of the billions of the human species who are living and have lived on this planet, no two were ever exactly alike. All have the distinctive qualities of human beings yet these are so combined that there is never precise duplication of personalities as wholes. In a less degree this wonderful sameness in the species and infinite variety in individuals is found in plants and animals. A study of the variations in number of vertebra in the human species and in other mammals indicates that man varies less in fundamental structure from the type than most of the higher animals. In mental characteristics, however, he varies a great deal more.
