Under the title, _Le monde physique, Essai de conception expérimentale_, M. Dr. JULIEN PIOGER offers to the public a sketch of a world-system. This system is summed up in the expression of “Universal Solidarity,” and is based on the idea of infinitely minute matter-particles, or “infinitesimals,” the mutual relations of which, and their equilibrium, constitute the machinery of the universe. The atomic-mechanical hypothesis, says M. Pioger, is wrong in resolving matter into perfected differential particles and in assigning to its atoms qualities which make of them either true material corpuscules or a real entity, “a thing in itself.” On the contrary, far from intending to assign a limit to materiality, the hypothesis of infinitesimals confines itself to limiting the conception which we may have of it. The infinitesimal corresponds to the infinitely small, that is to say to the non-perfected, to the non-differentiable, beyond our cognisance and our perceptivity; it expresses the most reduced condition of the affinities which constitute matter; it is the expression of the infinitesimal existence of that which we call motion, extension, ponderability, under the general name of matter. Now the most simple thing which can be conceived of in the physical world, is the _couple_ formed by the essential equipoise of two infinitesimals. In developing the couple it becomes possible to form the universe in all its great variety. The solidarity of the parts in the whole appears as the essential condition of existence of all that which Is—the necessary condition of all individuality. In conclusion I call attention to two new editions, one the well-known work of M. BERNARD PÉREZ, _Les trois premières années de l’enfant_, fifth edition, revised and supplied with an introduction by Mr. James Sully; the other _Les functions du cerveau_, by M. JULES SOURY, a work highly esteemed, embodying the most recent researches. LUCIEN ARRÉAT. FOOTNOTES: [46] Rueff, publisher. [47] This book and the following ones are published by F. Alcan. II. GERMANY. One of our foremost psychiatrists, Professor v. Krafft-Ebing of Vienna, says in his celebrated text-book on psychiatry: “If Pedagogy made a more serious study of the character of man in his psychopathological relations, many of the mistakes and severities of our system of education would be removed, many an unsuitable choice of vocation would be left unmade, and thus many a psychical existence rescued.” Any one who is at all familiar with the most important doctrines of the diseased phenomena of mental life, and who knows how frequently psychical disturbances of a more or less serious nature occur during childhood, will fully agree with Krafft-Ebing, and will only regret that pedagogy, in this important direction, has completely neglected its task.