33^ Journal of Comparative Neurology and Psychology. 



tactile discrimination is slightly more acute in the horizontal than in the vertical; 

 visual memory is both more rapid and subject to fewer errors in the horizontal 

 than in the vertical position; auditory memory shows the same result as the visual 

 memory; adding can be done more rapidly and with greater precision in the hori- 

 zontal posture; subjects show greater signs of fatigue in the horizontal than in the 

 vertical posture; a greater number of taps per minute can be made in the vertical 

 than in the horizontal position; and the vertical position is favorable to the strength 

 of grip." 



Wells, F. L. A Statistical Study of Literary Merit with Remarks on Some New Phases of the Method. 

 Archives of Psychology, no. 7, pp. 20- 30c. 1907. 



Yerkes, Robert M. The Dancing Mouse: A Study in Animal Behavior. Animal Behavior 

 Series, vol. i, pp. xxi + 290. New York: The Macmillan Company. 1907. 



It is not putting the matter too strongly to say that Dr. Yerkes has in this book 

 given us the most valuable contribution that has yet been made to the study of 

 animal behavior. Having become interested about four years ago in some speci- 

 mens of the curious Japanese dancing mouse, and finding them readily tamed, 

 easy to care for, and comparatively quick to learn, he undertook a thorough investi- 

 gation of their sensory equipment and intelligence. The results are stated clearly 

 and concisely in the present volume. Every step in the methods used, every stage 

 in the reasoning processes by which the author's conclusions were reached, is given, 

 so that the book is a real text-book in experimental method. 



The dancing mouse, as is well known, gets its name from the fact that when 

 placed in an open space it makes peculiar whirling or circling movements. These 

 movements have been thought to be due to a malformation of the equilibrium appa- 

 ratus in the ear, and support seems to be given to the theory by the fact that the 

 mice have defective hearing. Yet the statements of various experimenters who 

 have examined the ear are so conflicting that no definite inference can be drawn 

 from them. Dr. Yerkes concludes that to explain the peculiar movements of the 

 dancer "the structure of the entire organism will have to be taken into account," 

 and at the same time he finds no "satisfactory ground for considering the dancer 

 as either abnormal or pathological" — an assertion the truth of which would seem 

 to depend upon the meaning assigned to the term "abnormal." To account for 

 the disagreement among dift^erent observers of the behavior of the animal, some of 

 whom say that the mouse is markedly deficient in balancing power, while others 

 find no striking defect in this respect, Yerkes adopts the suggestion of Cyon that 

 there are at least two varieties of the dancing mouse, and has observed evidences 

 of the existence of two different strains among the specimens examined by 

 himself. 



The net results of the author's work with some four hundred individuals may be 

 grouped under four heads: those concerning the mouse's power of sense discrimi- 

 nation; those concerning its learning capacity; those bearing on questions of experi- 

 mental method, and those of interest to students of biogenetics. 



I. Three classes of sensory discriminations: auditory, brightness, and color, 

 were investigated. The mice of one of the two lines of descent represented were, 

 with the exception of one litter, throughout their lives insensitive to sounds. Those 

 of the other line showed sensitiveness for a day or two during their third week. 



