Literary Notices. 339 



occur with equal frequency and in such order that no particular kind of error occurs 

 repeatedly in succession." 



4. Finally, Dr. Yerkes made some studies on the phenomena of heredity in 

 the dancing mouse. The subjects of his experiments belonged to two separate lines 

 of dq^cent, which presented certain characteristic differences, the individuals of one 

 line being more like ordinary mice than those of the other line. Observations on 

 several generations indicated a certain inheritance in the latter line of descent of a 

 tendency to whirl to the left in dancing, while those of the former line showed no such 

 tendency. Four generations, a male and a female in each, were tested to see if the 

 training of the parents in white-black discrimination facilitated the learning process 

 in the offspring. The results showed no evidence of the inheritance of this acquired 

 character. 



From this superficial survey it will be seen how rich both in result and in sugges- 

 tion the book is. No less admirable is the spirit in which the work has been 

 carried on; a spirit of scientific conscientiousness, of modesty, and of humane 

 sympathy, untinged with sentimentality, for the animals experimented on. Of 

 comparative psychology, in the sense of an attempt to interpret the mental states 

 of the subjects, there is very little in the book, and that little does not strike one as 

 its most successful feature. For instance, when in labyrinth tests the procedure was 

 adopted of allowing a mouse, as a preliminary, to traverse the maze and escape 

 without getting an electric shock, it is said that this was for the purpose of allowing 

 the animal "to discover that escape from the maze was possible," but there is no 

 discussion of the terms in which such a possibility may have functioned in the mouse's 

 consciousness in subsequent tests, whether as a memory image or merely as an 

 increased tendency to movement. Again, when one method of reaction in the dis- 

 crimination experiments is designated "choice by comparison," one is left with the 

 interesting problem as to what sort of process the comparison of two stimuli in the 

 mouse's mind may be, and it might perhaps have been better to use a term that 

 would have had a less decided psychic implication. However, if there is but little 

 attempt at interpretation of the mental aspect of the facts observed, the book is 

 almost an ideal example of the kind of work which promises to put comparative 

 psychology on a firm scientific basis. 



MARGARET FLOY WASHBURN. 



Davis, H. B. The Raccoon: A Study in Animal Intelligence. American Journal of Psychology, 

 vol. 18, pp. 447-489. 1907. 



This paper describes the habits and instincts observable in adult raccoons in 

 captivity, and it presents the results of experiments to test learning, color perception, 

 and imitation in these animals, together with comparisons of these results with 

 those obtained by other investigators. In this review only the descriptions of experi- 

 ments and the discussion and interpretation of results will be examined. These 

 may be taken up under the general headings learning, color perception and imita- 

 tion, and comparisons. 



Learning. In the author's experimental study of learning the raccoons were 

 allowed to unfasten the door of a box, reach into it, and get food. Single fastenings, 

 a group of two and a group of three latches, and finally, two combination-locks, 

 each composed of four of the previously learned single fastenings, were used in the 



