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reflex actions and intelligence, but no instincts properly so-called. Con- sciousness is " a phenomenon superadded to movement and independent of it," and modifying neither the external excitation nor the reaction of the organism. The author recognises the difficulty of admitting " unconscious sensibility " and " unconscious sensations," but uses the terms with a have consciousness, " at least vague and confused " ; but there is no profit in observations on any but the human consciousness. In man there is consciousness of " sensation " and consciousness of " motility," to which a still more important element is to be added, viz., memory, which may be said to create consciousness and the unity of the Ego. Consciousness, in ultimate analysis, is " a succession of states of consciousness with recollec- tion". "Sensation is a physiological phenomenon, and perception is a psychological phenomenon." The laws of sensation agree (perhaps not exactly) with the laws of muscular irritability. Hence study of the laws of muscular contraction is the best introduction to physiological psycho- logy. " Emotions " are " sensitive instincts (as distinguished from " motor instincts ") with consciousness ". The will is essentially a " force of in- hibition," which may be exercised either by an " idea " or a " reflex " in a struggle against others. When the struggle between ideas is not on too unequal terms, we have the illusion of free-will. " Attention," " the best- defined form of will," is "an apparatus of excitability that reinforces images ". Finally, " intelligence " is " an explosive mechanism with con- sciousness and memory " ; for the essential character of organisms, that becomes more and more manifest as we ascend the zoological scale, is the power, which explosive substances also possess, of setting free large amounts of energy in response to a slight initial change ; and this character is most of all manifest in the phenomena of intelligence, these being organically the highest. Uancienne d la nouvelle Philosophic. Essai sur les Lois gene"rales du De- veloppement de la Philosophic. Par E, DE ROBERTY. Paris : F. Alcan, 1887. Pp. vi., 364. This volume is the first part of a work which, as projected by the author, will consist of six similar parts. His system may be described as a modi- fied Positivism. The object of his first volume is to study the philosophy of the past and present as " a social fact," necessary in a certain stage of evolution, but destined to give place to the synthesis of the sciences which is to be the philosophy of the future. He accepts Comte's law of the three states, but only as an empirical formula deducible from more fundamental laws, viz., " the law of the three types of metaphysics " and " the law of correlation between science and philosophy ". Theology and metaphysics alike are hypothetical theories of the universe constructed in the absence of a sufficient basis of positive science ; theology being essentially an infe- rior and popularised form of philosophy, existing in general side by side with metaphysics. Metaphysical hypotheses are of three types Material- istic, Idealistic and Sensualistic. Every metaphysical hypothesis is an attempt to explain the universe in terms of the phenomena that form the subject-matter of one particular group of sciences. Thus the materialist ex- plains all phenomena by reference to the laws of inorganic nature, while the idealist explains them all by reference to the higher psychical and social phenomena. These two forms of metaphysics are contemporaneous in origin and continue to exist side by side. Materialism is a kind of premature positivism. Idealism has the characters of a reaction and tends to attach