makes life and history tingle with such a tragic zest, may not be an illusion. As we grant to the advocate of the mechanical theory that it may be one, so he must grant us that it may not. And the result is two conceptions of possibility face to face with no facts definitely enough known to stand as arbiter between them." And he adds that one can leave the question open, or let one's general philosophy incline the beam. In his own case, for ethical reasons unstated, he sides with the believers in the cause-theory, or that consciousness is a spiritual force.
The remainder of Vol. I is Chapter XII, Conception; Chapter XIII, Discrimination and Comparison; Chapter XIV, Association; Chapter XV, The Perception of Time; Chapter XVI, Memory. They are spirited and in(ter)esting, and especially instructive to teachers.
The opening chapter of Vol. II is upon Sensations, and discusses such general questions as the Cognitive Function of Sensation and The Relativity of Knowledge, which answers the question whether our objects of knowledge contain absolute terms or consist altogether of relations. These sections occupy twelve pages of the chapter, and the remaining thirty pages are devoted to The Law of Contrast. Then follows the chapter on Imagination, which contains an especially interesting section upon the differences of individuals in the power of imagination. The work done in this field by Fechner and Galton is set forth, and Mr. James gives also the results obtained from his own psychology-students' descriptions of their power of visual imagination. The entire chapter is very readable, although less disputatious than usual. The next three chapters are upon The Perception of Things, The Perception of Space, and The Perception of Reality, the two latter being among those the beginner is advised to omit on a first reading. The chapter on Reasoning is popular and entertaining. Of course, Mr. James insists on the intellectual contrast between brute and man, and does not admit any of the instances adduced by evolutionists to prove that the essential mental process involved in reasoning is sometimes exhibited by dogs and elephants. The chapters enumerated occupy 382 pages of the volume. The next three chapters, occupying 200 pages, are upon Instinct, The Emotions, and Will. There is a short chapter on Hypnotism, in which the various theories concerning it are discussed in the usual vein. These theories are (1) Animal Magnetism; (2) Neurosis; and (3) Suggestion, the latter of which, Mr. James says, is quite triumphant at the present day over the neurosis theory, as held at the Salpêtrière.
The last chapter in the book, on Necessary Truths and the Effects of Experience, is an elaborate effort to discredit all attempts of the experience philosophy to explain the genesis of our mental structure. As Mr. Spencer is the thinker who has done most in this direction, of course it is his especial doctrines that are first of all overthrown. This is done in the usual way by means of half statements and unwarranted assumptions. To gain his point he regards the process of adaptation, which Mr. Spencer calls direct equilibration, as the way of experience proper, the front-door way, but the process which Darwin named "accidental variation," and which Mr. Spencer terms indirect equilibration, he calls the back-door way, and says: "Both these processes are of course natural and physical; but they belong to entirely different physical spheres." (The Italics are ours.) This is a pure assumption, the contrary of which is made more and more manifest as the observations of naturalists are extended. Yet on this assumption the meaning of experience is given as "processes which influence the mind by the front-door way of simple habits and association" (the Italics are the author's); and backdoor processes are said to be "pure idiosyncrasies, spontaneous variations, fitted by good luck to take cognizance of objects without being in any intelligible sense immediate derivations from them." It is in such ways as this that Mr. James is able to be both scientist and metaphysician, evolutionist and anti-evolutionist, as the peculiarities of his own mind determine.
A Text-book of Comparative Physiology. By Wesley Mills, M. D., D. V. S. New York: D. Appleton & Co. Pp. 636. Price, $3.
Like the author's Text-book of Animal Physiology, recently published, this work is designed primarily for students and practitioners of veterinary medicine. It is intended to replace the text books of human physi-