xxx SCIENCE PROGRESS. 



one part of the brain to another. Further, and this is the chief defect of the volume, the 

 author seems very imperfectly acquainted with the wide harvest of facts gathered in recent 

 years by the delicate method of Wallerian degeneration. Such errors as occur in his 

 description on pp. 16 and 17, for instance, are due to want of acquaintance with the Wallerian 

 results. Finally, Professor Bechterew does not appear to have grasped the difference existing 

 between atrophic degeneration (or the secondary atrophy of Gudden) and the Wallerian 

 degeneration. The phenomena are fundamentally and absolutely distinct. The latter process 

 is confined to the actual nerve cell upon which the lesion (mechanical injury or what not) is 

 inflicted ; in the former phenomenon the field occupied is a whole physiological chain, or at 

 least several links of a chain of functionally connected nerve cells. 



When the work reaches, as we hope it may, a second edition, the author should bring it 

 thoroughly up to date ; the more so that in his preface he expresses his purpose in issuing the 

 work to consist chiefly in the furnishing to busy students and practitioners a comprehen- 

 sive account of the ' ' Gegenwartige Stand der Frage fiber die Leitungsbahnen des Hirns 

 und mindestens den grossten Zeit der in dieser Hinsicht bekannten Thatsachen ". 



The figures in the text are very good, though very schematic. Several of them are 

 original. 



Movement. By E. J. Mary, Member of the Institute and of the Academy of Medicine, 

 Professor at the College of France, Director of the Physiological Station. Translated 

 by Eric Pritchard, M.A., M.B., B.Ch. (Oxon.). London: William Heinemann, 1895 



The advances made in photography during the last few years have been very great, and 

 in no direction have these advances been more remarkable than in the representation of 

 movements which take place too rapidly to be followed by the unassisted eye. Professor 

 Boys' photographs of flying projectiles, Dr. Worthington's of the splash of a drop, and 

 others are illustrations of this. The visit of Mr. Muybridge to England some years 

 ago and the exhibition of the results he had obtained by means of his ingenious apparatus 

 brought prominently to the notice of the public, scientific and otherwise, the great strides 

 which had been made in the analysis by means of photography of animal locomotion, 

 and the appearance of Mary's book in France showed that considerable attention was being 

 given to the subject in that country also. 



Unfortunately in England the amateur photographer, to whom we owe almost all the 

 advances that have been made in photography in recent years, is, as a rule, almost entirely 

 ignorant of scientific matters outside his own subject, and therefore much talent is wasted for 

 want of a definite object to follow out. It is therefore a subject for congratulation that a 

 translation of Mary's work has appeared, and that it is well calculated to appeal to unscientific 

 readers. In Mary's Movement, as in so many French scientific works, the style is admirably 

 clear, and the explanations of even complicated pieces of apparatus such as to be easily 

 understood. The scope of the work is wide— indeed it forms a good summary of the 

 whole subject of the representation of movement by the graphic method assisted by photo- 

 graphy. The measurement of space and time is treated in the preliminary chapters, and 

 later on the application of these measurements and the assistance rendered by photography 

 in such application to the elucidation of problems in movements of animate and inanimate 

 objects. Locomotion in man, in quadrupeds, in fish, birds and insects is thus analysed. 



In the case of the complicated rhythms of the locomotion of quadrupeds some 

 difficulty is usually experienced in understanding the sequence of events, and it is therefore 

 advisable to use every means in our power to render the representation of such movement as 

 simple as possible. In some of the figures of horses in motion (e.g. , fig. 7, p. 9) it would have 

 been simpler to have arranged the graphic records to read in the same direction as the horse 

 is travelling in the figure, and in any case some indication should be given of the direction in 

 which the record is to be read. The facts that the animal is travelling in one direction, 

 that the record reads in the opposite direction, and that there is no indication of this, renders the 

 figure puzzling to any one unused to the interpretation of graphic records. 



In fig. 22 the description in the text does not correspond with that under the cut. In 

 the former the convex surface of the card strip is to be blackened, in the latter the inner surface 

 is said to be blackened. 



Most of the figures, however, are well executed and judiciously selected, and are so 

 numerous that even unscientific readers will find no difficulty in following the descriptions of 

 the apparatus by means of which such excellent results have been obtained. 



Of especial interest are the pages devoted to a description of the application of the method 



