XVIII THE DEGRADATIONS OF LOVE 198 XIX THE FAULTS AND CRIMES OF LOVE 211 XX THE RIGHTS AND DUTIES OF LOVE 219 XXI THE COVENANTS OF LOVE 227 FOREWORD Mantegazza is to Physiology what Flammarion is to Astronomy. The two great masters head a brilliant galaxy of modern writers on natural phenomena who draw their material from science and mould it in an esthetic form. After the most skilful analysis of the scientific elements to their minutest components, they proceed to an ideal synthesis in which the various elements retain their substance, yet change their outward appearance. It seems as if these elect minds, having once satisfied their scientific curiosity as to physical and human phenomena, had been fascinated and inspired by an irresistible love of creation, and rising above the facts and laws of nature to the evanescent and melodious world of imagination, they offer us their work in a harmonious unity of two seemingly opposite and irreconcilable elements--the real and the ideal, Science and Poetry. And thus, I dare say, it is as if, by a generous law of reaction and equilibrium, while our generation seems to gravitate toward a life of facts and order, barren of idealism, Science would teach us that she herself does not benumb or kill sentiment, but, on the contrary, discloses to the minds of the elect the flowery slopes of an unknown and infinite world of wonders and sentiment.