[3] According to Laurent (“Morbid Love,” pp. 133, 134, Leipzig, 1895), common prostitutes generally use musk; young working women, violet or rose-water; ladies of the bourgeoisie, penetrating perfumes, such as white heliotrope, jasmine, and ylang-ylang; women of the half-world, finer perfumes, or such “as are complex, like their own mode of life”--for example, lily-of-the-valley, or mignonette. CHAPTER II THE SECONDARY PHENOMENA OF LOVE (BRAIN AND SENSES) “_From these considerations it follows that man, in the course of his phylogenetic development extending through lengthy geological periods, has lost numerous advantages; and the question arises whether, in exchange for these, he may not also have gained certain other advantages. Such must, indeed, have been the case if the human species was to remain capable of survival. There has been a_ process of exchange, _by means of which man has gained an equivalent for all the qualities he has lost. And the gain consists in the_ unlimited plasticity of his brain. _By this he is fully compensated for the loss of the large and long series of advantages which his remote predecessors possessed._”--R. WIEDERSHEIM. CONTENTS OF CHAPTER II The secondary phenomena of sexuality -- Their connexion with the nervous system and the sense organs -- The brain as criterion of human sexuality -- Its development proportional to the retrogression of other parts -- Example of the organ of smell and of the mammary glands -- Relative retrogression of the female clitoris -- Variation of the female genital organs -- Reduction of the hairy covering of the skin -- Theory regarding the origin of the comparative baldness of the human species -- Assumed connexion with climate -- With dentition -- Influence of artificial clothing -- The hygienic and æsthetic significance of the loss of hair -- The reason why the axillary and pubic hair have been retained -- Sexual influence of the hair of these regions and of the hair of woman’s head -- Gradual retrogression of the male beard -- The change of bodily type under the influence of the brain -- The way of the spirit in love -- The pure instinctive in the sexuality of primitive man -- His lack of the idea, “love” -- Analogy of this state among the lower classes of the present day -- Periodicity of the sexual impulse in the time of primitive man -- Periodicity amongst savage races of to-day -- The researches of Fliess and Swoboda -- The twenty-three day “masculine” and the twenty-eight day “feminine” periods -- Menstruation -- A peculiarity of the human female -- The origin of enduring love in mankind -- Love rendered more enduring by the spirit -- Kant’s views on the subject -- Hypothesis of W. Rheinhard and Virey -- The complication of the sexual impulse through sensory stimuli -- Buddha’s speech to the monks -- The prepotency of the higher senses -- The sense of touch -- The skin as