In summing up, therefore, the analogies between sex worship and nature worship, the following features may be reviewed: the outward form is the same, _i. e._, that of a religious ceremonial rite in which a sacred object is the representation of the deity. The symbolism associated with this object develops in the same way in both instances. In the course of time this symbolism becomes conventionalized, and eventually it finds its way into primitive art. It then becomes the leading motive in primitive art and finally the religious motive is forgotten and the aesthetic motive alone remains. Were further proof necessary, these analogies alone would be sufficient to enable us to understand the meaning of sex worship. The ritual associated with the worship of sex then, arose in response to emotions which are grouped around the instinct of reproduction. These feelings are so primitive and at the same time so fundamental, that it is difficult for us to realize that early man should dignify them by religious ritual. They stand out as expressions of a biological demand. As stated above, sex worship was not a conscious expression on the part of certain individuals, but it was the unconscious expression of longings and desires on the part of the race. It represents a phase in man's mental evolution, a process of mental development. Its dynamic value, from a biological standpoint, is at once apparent. In order to survive man must reproduce his kind, and the emotions associated with reproductive instincts must be of adequate dynamic value. * * * * * It has been stated that sex worship, as practiced during the primitive state of civilization, was a healthy phase in racial evolution. In a higher degree of civilization, however, the reversion to this motive was a regression, and decadent sex worship as it existed during the middle ages was an attempt by certain unhealthy elements in the race to revert to the primitive. In decadent sex worship we are dealing with an instance of faulty mental adaptation in a way in which we had not been accustomed to consider it. It is a case of faulty adaptation in the race, or at least in certain elements of it, rather than in the individual. These general analogies are noteworthy from the standpoints of mental evolution and abnormal psychology. In order to show how sex worship as practiced by a later civilization was the expression of an unhealthy tendency, we must digress sufficiently to show the setting in which decadent sex worship existed. It is necessary to give a chronological outline indicating how primitive beliefs succeeded each other as a result of man's progressive development.