NEW BOOKS. 547 the Middle Ages, the Renaissance, and the seventeenth, eighteenth and nineteenth centuries, are taken up in turn. The chief topics discussed are mechanics, electricity and magnetism, heat, sound and light. Magnus and Lord Kelvin seem to be rival claimants for the honour of having established the first physical laboratory. L'lnstabiKM Mentale, Essai sur les donne'es de la Psycho- Pathologie. Par G. L. DUPRAT, Professeur de Philosophic, Docteur es lettres. Paris : Felix Alcan, 1899. The aim of this book is to place the main results of recent psycho- pathology in their proper philosophical setting. The book is largely a " criticism of categories " ; but it is, at every page, informed of the con- crete material. It is well-arranged, lucid, and reasoned. The author, starting from the most abstract considerations of space and time and of the ultimate relations of neurosis to biosis, arrives at the inexpugnable unity of consciousness (or rather personality) as the fundamental fact. In passing (c. i., p. 15), he reminds the physiologist that his " plastides " are incapable of self-existence. So are the groups of them that form nerve, muscle, organ, and organism. " Mais n'est-il pas plus aise de comprendre ce systeme quand on se dit que chaque element est un conscience representative d'autrui ? " The solidarity of the " plastides " is the harmony of elementary consciousness. A "hierarchy of nerve centres " is " dans une theorie purernent physiologique radicalement in- comprehensible " (p. 16). Which is to say that we are concerned with a psycho-physical organisation, and perhaps it is well, as here, to drive this home for the edification of the abstract biologist. But the impression one gets from this chapter is that the " unity " has swallowed up the " di- versity " without the " labour of the notion ". But M. Duprat rapidly passes to more concrete matters. A centre nervous or mental is a synthesis of relations. Time-relations are " constitutive du tout sujet," and, therefore, since this implies distinction, opposition, there is, at the basis of the psychical life "une discontinuity fonciere, une instabilite radicale ". But, for apperception of perceptions, duration is necessary. The discontinuity is overcome by the concept of " devenir " (becoming, transition, process, growth, activity, evolution : the term is so common through the book that I offer various renderings). With these first principles, M. Duprat finds the normal to lie not in the average, or general, but in the ideal, which is system, or systematisation. The morbid is, by contrast, the asystematic, or rather that which does no- wise achieve system. " The evolution of a mind presents a progress or a regression, and in this progress or regression a rhythm." This evolu- tion is " the gradual passage by suitable increments (intermediaires con- venables) from one state to another more complex or less complex ". Psychical states are systematised by the tendency towards an end, a determinate personality, permanent amid changing environment (p. 58). From this standpoint, chap. iii. endeavours to define a psycho-patho- logical fact. The chapter is good and faces fairly the difficulty of marking off diseased activity from normal function. But the net re- sult is not peculiarly convincing. A morbid mental phenomenon would be : "a conscious moment or a series of conscious moments that by the discontinuity of psychical evolution manifests the law of mental instability to the detriment of the systematic growth of a personality " (du devenir systematique d'une personalite) (p. 77). In part ii., M. Duprat introduces us to "les faits psyeho-pathologiques." Mental disease due to the destruction of " a group of inferior elements " (p. 80)
