A law regulating and governing phenomena is only possible on the assumption that the law is the expression of the modus operandi of the governing power which has established the fixed rules for the performance of a certain action leading to a certain end. The law governing the phenomena of sex has evidently been prescribed for the purpose of the preservation of the species. This preservation is at the basis of sexual desire, and because the ultimate aim is unknown to the agent, the desire is instinctive in nature. For every instinct is an inward impulse, an unconscious, involuntary prompting to action, without a distinct apprehension of the end which nature has designed should be accomplished thereby. Hunger for love and hunger for food are both based upon the two instincts of preservation, the instinct of the preservation of the individual and the instinct of the preservation of the kind. The hunger for food, manifested already by the new-born baby,[T] is based upon the instinct of the preservation of the individual, the sex-urge, manifested by youths and maidens at the time of puberty, before they have ever experienced any copulative libido, is based upon the instinct of the preservation of the species. The active principle of the mind, which is energetically devoted to the gratification of the sensual desire and the state of mind which is constantly yearning to satisfy the sensual want, are the promptings of this instinct. They exist at this early period independent of all experience. The absorbing feeling which seeks the consummation of its purpose, as well as the selection of the means to be employed, is not based upon previous experience. They are internal, unconscious messages which give rise to the conscious impulses, without waiting for the external stimuli which, later on, coöperate with the impulse to affect the nervous centres. The conscious impulses, composing the sexual instinct, are, according to Moll, the impulse of contrectation, or the desire to effect a real or a virtual contact with an individual of the opposite sex, and the impulse of detumescence, or the desire to effect a certain material and nervous discharge. Any inclination, to become an impulse, must possess two qualities: it must move the individual to commit an act in which logic and calculation have no part; and secondly, while committing the act, the individual must be conscious of its immediate aim. The two component impulses of the sex-instinct possess these two qualities. They are unreasoning promptings to actions, the end of which is present in the individual’s consciousness.