with the collaboration of P.-H. BENOIT, G. BLET, and P.-V. BERARD). 1950. Masson, Paris. Pp. 864, 455 figs. (Fr. 3,400). Most review articles and monographs, however comprehensive, are almost unreadable because they are only compilations of the literature with no form or thesis to carry the reader along. In addition, one often finds entirely incompatible theories or results presented in adjacent paragraphs (or even sentences) with no indication whether one is more acceptable to the experts than

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... the other. " La vision nocturne et ses troubles," which was originally prepared as a report for discussion by the Societe Fran9aise d'Ophtalmologie, does not suffer from these faults in spite of its immense scope (it is hardly possible to think of a book or paper concerned, even indirectly, with normal or abnormal dark-adaptation and night vision which has not been included). This is certainly no mere collection of the relevant literature. Where results or theories are in conflict, the authors usually make a satisfactory attempt to guide the reader in choosing between them, and there is an excellent critical discussion of current theories about the mechanism of dark-adaptation. It is almost impossible to overpraise this excellent book. Not only is it of firstrate quality but it is entirely up to date, several papers published as late as 1950 being included. The necessary background of the structure, function, and centra connections of the retina is well covered before dark-adaptation and night visionl, with the factors affecting them, are discussed. One of the niost valuable sections of the book comprises Chapters VII and VIII. The former gives an almost comprehensive list of the numerous types of adaptometer, both in use and described in the literature. In addition, there is a full description of how each works, what it actually measures (absolute threshold, difference threshold, resolving power, etc.), and what information it can be expected to give. Chapter VIII deals with the different techniques of investigation and methods of presenting results. To anyone trying to find his way through the jungle of dark-adaptation literature, or to compare the results of different workers, this chapter will be invaluable. However, it is not only those concerned with dark-adaptation and its disorders who are deeply indebted to the authors of this splendid volume. Those interested in retinal physiology as a whole will also find much that is valuable and important. Those who were acquainted with Adler's " Clinical Physiology of the Eye "' which appeared twenty years ago will be glad to welcome its successor. It is a tribute to the virility of ocular physiology that the author has found that an entirely new book rather than a second edition of the old is required, for not only has much in basic physiology changed, but many of the applications of these problems to the eye have taken on new aspects-the dynamics of the intra-ocular fluids, the photo-chemistry of vision, and the electro-physiology of the visual impulse, to mention three examples. on 23 July 2018 by guest. Protected by copyright.