So it must be that those who have attained a high place in intellectual life will gladly replace the old conception of physical and human phenomena with a new and more intense representation, which, measured in the finitude of our reason, is loved in the infinity of our sentiment. To the uninitiated mind most beautiful is the representation of the sun in the image of Phoebus crossing the heavens in his flaming chariot drawn by fiery horses; but still more beautiful for the intellectual mind is it to think of the immense body of fire, of the energy darting from a star more than a hundred million miles distant from our planet, more than a hundred million times larger than the earth, and yet a star millions of times smaller than millions of other celestial bodies to our naked eye unknown, unknown to our most powerful telescopes, and whose existence and fantastic speed in the space of the heavens are divined only by the abstraction of our faculties in an infinite representation of the laws of physics. Poetical is the vision of a goddess of Olympus descending to earth and carrying to a man asleep the message or the image of a dear, distant person; but immensely more poetical is the conception of a telepathic force within us, made of us, consciously or unconsciously created by us, an integral part of our psychical organism, and by which we instantly communicate over hills and dales, mountains and valleys, oceans and deserts, with another human being whose spirit is harmoniously attuned to ours. The impersonation of hatred and love by Fury and Cupid is much less poetical than the conception of an explosion of psychical forces, powerful and antagonistic, in millions of men at the same time. The task of dealing with the natural history, the origin and the development of the sentiment which underlies the principal phenomena of human existence, which came into being with the first twilight of organic life, and which indissolubly binds together the individuals and the generations, seems to have been reserved to the genius of Paolo Mantegazza, and with this great subject he dealt in a masterly way, in a way unimitated and inimitable. He has snatched Love from the Olympus of the gods of old, from the clutches of classic literature, stripped him of all his tinsel and garments, and revealed him as part--flesh and blood of man. By a new conception of love, more rational, more human and yet no less poetical than the classic representations to which we have been accustomed from times immemorial, Mantegazza gives us a work in which the scientific foundation and the poetical conceptions are united in such wealth of colors and harmonies that its reading, rich with true and romantic charm, is incomparably superior to our best fiction. It is a daring deed, both in the literary and the philosophical field, and it opens a new horizon to the idealization of human feelings, discoveries and events.