Love, although a most powerful affection, always follows the laws of elementary physics, which govern all the energies accumulated in our nervous centers and which we call sentiments. As long as passion remains in a condition of desire, that is to say, as long as force is potential and is not turned into a product, energy lasts and sentiment lives, vigorous and ardent. All the art of preserving love is, therefore, reduced to this alone: to preserve desire and to cause it to spring up again almost immediately after it is spent. And as even love, with all its omnipotence, cannot evade the physical laws, and every spark that springs forth must always be followed by a period of repose, it is indispensable to act in such a way that while a part of the force is transformed into labor, another be accumulated, preparing a new spark in such a short time that it should be nearly impossible to perceive any interval between the two sparks. To transform the intermittent electric current into a continuous one constitutes the great secret of protracting the existence of love. As long as desire is not satisfied, and the struggle has not become a conquest, love is not only preserved but increased; and not in vain does woman provide for her happiness in asking for time and prolonging the battle. A love must be either very weak or very brutal if it withdraws from the struggle before victory; and as it happens very seldom that a woman yields everything at once, the small and great favors which from time to time she concedes to the conqueror mark a continual renewal of ever ardent desires and a continuous revivification of love. Finally, sooner or later, the day of the wished-for victory arrives, and one embrace makes two lives one, melts in a single crucible two volcanic rocks and two feelings of voluptuousness. However, even when love is so base as to be only a thirst for pleasure, it seldom dies with the first embrace. And who can say that he has possessed a woman entirely in one night of love? Human charms are such and so many, and our esthetic needs so exquisite and ardent, that even the acquisition of voluptuousness alone is, fortunately, very slow, and in the sweet occupation of new provinces love is preserved or revivified. The various treasures of beauty and sensuality of two lovers, the art of loving, so neglected even after Ovidius' times, mark the limit of duration of those loves that derive their energies only from the worship of form or from the ardor of voluptuousness; and if in some cases that duration is long-lasting, it never is infinite. The hour comes when, alas! the wing of time smites the fresh cheeks of youth, and the northern winds wrinkle them, and the storm scatters over the ground the rosy petals of human beauty; the hour comes when the cup of lust no longer contains a drop of nectar, and then, if nothing is left, love is dying, and no miracle in the world can save it from a certain death. The energy of passion had