It should be borne in mind that the characteristic changes from one period to another are not abrupt transitions, but easy gradations; a gradual dropping of the distinctive features of the period left behind for the essentials of the period just attained. The progression is by easy, continuous stages, effected unconsciously and unobtrusively. This growth may be compared to the four periods of the development of a plant; first, the bursting of the seed into life and the tender stalk forcing its way upward into the light--the infantile period; then the formation of branches and leaves and the growth of stalk--the early boyhood period; then the putting forth of the bud which is the precursor of the flower, and the formation and development of petals, stamen, pistils, and pollen--the adolescent period; and finally the blossoming forth of the full-blown flower, the fertilization of the pistil by the pollen of the anther, the whole marvelous process of reproduction culminating in the formation of the embryonic plant contained in the seed--the period of maturity. All of these stages are characterized by an evolution which is as gradual as it is silent. In like manner it should be understood that the ages delimiting the four periods of boyhood are somewhat arbitrary and are subject to the controlling factors of race, climate, health, and individual temperament. The Latin races mature earlier than the Anglo-Saxon; the boy in the tropics reaches puberty more quickly than one in a colder zone; certain abnormalities of physical condition, as well as environment and heredity, conduce to early maturity; and temperamental characteristics contribute, in some degree, to a difference in the time required to traverse the various periods of boyhood. I have known boys of ten who were still infants, and I have in mind a boy friend of sixteen years, with the normal mental development of one of that age, in whom adolescence has not begun. Physically and psychologically he is eleven years old, although chronologically he is sixteen. He is, therefore, in the individualistic period of his existence and, in a large degree, he should be judged, governed, and trained by the rules applicable to that period. In so far as his moral concepts are influenced by mentality, his responsibility for deflection is that of one of his chronological age; but in that class of cases in which his moral viewpoint is controlled by his undeveloped physical or psychic state, his responsibility belongs to the individualistic period to which these qualities are attributable.