An especially important chapter in the history of woman at this period of life relates to the dietetics of pregnancy and parturition, and to the regulations to be observed for the maintenance of health at this time and in connection with the processes of pregnancy, parturition, puerperal involution of the uterus, and lactation. This subject cannot now however be considered at length, and for our present purposes it is sufficient to point out how important it is alike for mother and child, alike for family and society, that the ever more and more widely and generally diffused practice of the artificial feeding of infants should be abandoned, and that there should be a return to the natural method according to which each mother nurses her own infant. The prevailing custom costs every year thousands of mothers their health, and thousands of children their lives. COPULATION AND CONCEPTION. _Copulation._ The reproduction of the species is effected by means of an act of copulation on the part of a male and a female individual, both of whom must have attained complete sexual development. In all the sequence of reproductive processes it is copulation alone that is a voluntary act, all the other processes being independent of the will and even of consciousness. A characteristic difference between man and the lower animals lies in the fact that in the human species sexual pleasure and the act of copulation may occur at any season of the year; and a further characteristic difference may perhaps be found in the fact that in the great majority of individuals of the human species the psychical process of “love” plays a determinative part. _Voltaire_ pointed out that to man alone among animals are known the embrace and the joy of the kiss. The significance of the kiss is depicted by _Grillparzer_ in the following verses: Auf die Hände küsst die Achtung, Auf die Wangen Wohlgefallen, Seelige Liebe auf den Mund. Auf den Nacken das Verlangen; Uberall sonsthin Raserei.[45]