Were we to open this book about the middle we should be disposed to set it down, on the strength of its latter half, as a contribution to the literature of the Pleasantonian (or blue-glass) school of natural philosophy. This impression would be humored by the bluish tint of the paper upon which it is printed. But an inspection of the entire work would show that it is something more comprehensive and ambitious, not to say more interesting and suggestive. It is the product of a bold and original, if not exactly close and systematic, thinker--one who, with a longer and severer experimental training in the fields he has chosen for exploration, would command the respectful attention of leading scientific men. He begins with the reflection that, "in spite of the wonderful achievements of experimental scientists, no definite conceptions of atomic machinery, or the fundamental processes of thermal, electric, chemical, physiological or psychological action, have been attained." He proposes to remedy this failure, and to carry the natural sciences to their "basic principles." He proceeds to speculate with great ingenuity on the nature of light, the form, relations and movements of atoms, the action of electricity upon them, the constitution of the atmosphere, mode of creation of the solar system, and the _rationale_ of chemical affinity. From these lofty regions he stoops to his conclusion in the new science of "chromo-therapeutics." He undertakes to define and explain the alleged effects upon mind, soul and body of all the colors of the spectrum. Among these colors he assigns the place of honor to blue, that tint emanating from the frontal portion of the brain in rays visible to certain finely-organized individuals, and being associated with the highest intellectual faculties. Red belongs to the opposite pole of the cerebral sphere, and holds special relations with the grosser part of man's abstract nature. In this mysterious region of inquiry he joins hands with some questionable allies, such as the Spiritualists, the phrenologists and the mesmerizers. The power of the clairvoyants he does not doubt. Indeed, he claims to have used it himself, and to have fattened on it, his present weight of one hundred and eighty pounds having been attained, he tells us, together with perfect health, by the judicious employment of "these subtler agencies." One is tempted to ask, in view of such a result, why waste time on the color-cure when the mesmeric system succeeds so admirably?