that the preceding condition of the free larva (caterpillar, grub, or maggot) included a highly developed psychic activity, and that this is, significantly, lower than the stage which is seen afterwards (when the chrysalis sleep is over) in the perfect, winged, sexually mature insect. Man's psychic activity, like that of most of the higher animals, runs through a long series of stages of development during the individual life. We may single out the five following as the most important of them: I. The soul of the new-born infant up to the birth of self-consciousness and the learning of speech. II. The soul of the boy or girl up to puberty (_i.e._, until the awakening of the sexual instinct). III. The soul of the youth or maiden up to the time of sexual intercourse (the "idealist" period). IV. The soul of the grown man and the mature woman (the period of full maturity and of the founding of families, lasting until about the sixtieth year for the man and the fiftieth for the woman--until _involution_ sets in). V. The soul of the old man or woman (the period of degeneration). Man's psychic life runs the same evolution--upward progress, full maturity, and downward degeneration--as every other vital activity in his organization. CHAPTER IX THE PHYLOGENY OF THE SOUL Gradual Historical Evolution of the Human Soul from the Animal Soul--Methods of Phylogenetic Psychology--Four Chief Stages in the Phylogeny of the Soul: I. The Cell-Soul (Cytopsyche) of the Protist (Infusoria, Ova, etc.): Cellular Psychology; II. The Soul of a Colony of Cells, or the Cenobitic Soul (Coenopsyche): Psychology of the Morula and Blastula; III. The Soul of the Tissue (Histopsyche): Its Twofold Nature: The Soul of the Plant: The Soul of the Lower, Nerveless Animal: Double Soul of the Siphonophora (Personal and Kormal Soul); IV. The Nerve-Soul (Neuropsyche) of the Higher Animal--Three Sections of its Psychic Apparatus: Sense-Organs, Muscles, and Nerves--Typical Formation of the Nerve-Centre in the Various Groups of Animals--Psychic Organ of the Vertebrate: the Brain and the Spinal Cord--Phylogeny of the Mammal Soul