Jung explains the polymorphism of these phenomena as arising from a gradual movement of the libido from exclusive service in the function of nutrition into new avenues which successively open up with the development of the child until the final inauguration of the sexual function proper at puberty. Normally these childish bad habits are gradually relinquished until the libido is entirely withdrawn from these immature phases and with the ushering in of puberty for the first time “appears in the form of an undifferentiated sexual primitive power, clearly forcing the individual towards division, budding, etc.” However, if in the course of its movement from the function of nutrition to the sexual function the libido is arrested or retarded at any phase, then a _fixation_ may result, creating a disturbance in the harmony of the normal development. For, although the libido is retarded and remains clinging to some childish manifestation, time goes on and the physical growth of the child does not stand still. Soon a great contrast is created between the infantile manifestations of the emotional life and the needs of the more adult individual, and the foundation is thus prepared for either the development of a definite neurosis or else for those weaknesses of character or symptomatic disturbances which are not sufficiently serious to be called a neurosis. One of the most active and important forms of childish libido occupation is in phantasy making. The child’s world is one of imagery and make-believe where he can create for himself that satisfaction and enjoyment which the world of reality so often denies. As the child grows and real demands of life are made upon him it becomes increasingly necessary that his libido be taken away from his phantastic world and used for the required adaptation to reality needed by his age and condition, until finally for the adult the freedom of the whole libido is necessary to meet the biological and cultural demands of life.