The Dancing Mouse | Page 2

animal behavior. It is small, easily cared for, readily tamed, harmless, incessantly active, and it lends itself satisfactorily to a large number of experimental situations. For laboratory courses in Comparative Psychology or Comparative Physiology it well might hold the place which the frog now holds in courses in Comparative Anatomy.
Gratefully, and with this expression of my thanks, I acknowledge my indebtedness to Professor Hugo Münsterberg for placing at my command the resources of the Harvard Psychological Laboratory and for advice and encouragement throughout my investigation; to Professor Edwin B. Holt for valuable assistance in more ways than I can mention; to Professor Wallace C. Sabine for generous aid in connection with the experiments on hearing; to Professor Theobald Smith for the examination of pathological dancers; to Miss Mary C. Dickerson for the photographs of dancing mice which are reproduced in the frontispiece; to Mr. Frank Ashmore for additional photographs which I have been unable to use in this volume; to Mr. C. H. Toll for the drawings for Figures 14 and 20; to Doctors H. W. Rand and C. S. Berry for valuable suggestions on the basis of a critical reading of the proof sheets; and to my wife, Ada Watterson Yerkes, for constant aid throughout the experimental work and in the preparation of this volume.
R. M. Y.
CAMBRIDGE, MASSACHUSETTS,
August, 1907.

CONTENTS
LIST OF ILLUSTRATIONS
LITERATURE ON THE DANCING MOUSE
CHAPTER I
CHARACTERISTICS, ORIGIN, AND HISTORY
Peculiarities of the dancing mouse--Markings and method of keeping record of individuals--The dancer in China and Japan (Kishi, Mitsukuri, Hatai)-- Theories concerning the origin of the race: selectional breeding; the inheritance of an acquired character; mutation, inheritance, and selectional breeding; pathological changes; natural selection--Instances of the occurrence of dancers among other kinds of mice--Results of crossing dancer with other kinds of mice.
CHAPTER II
FEEDING, BREEDING, AND DEVELOPMENT OF THE YOUNG
Methods of keeping and caring for dancers--Cages, nest-boxes, and materials for nest--Cleansing cages--Food supply and feeding--Importance of cleanliness, warmth, and pure food--Relations of males and females, fighting--The young, number in a litter--Care of young--Course of development--Comparison of young of dancer with young of common mouse-- Diary account of the course of development of a typical litter of dancers.
CHAPTER III
BEHAVIOR: DANCE MOVEMENTS
Dancing--Restlessness and excitability--Significance of restlessness-- Forms of dance: whirling, circling, and figure-eights--Direction of whirling and circling: right whirlers, left whirlers, and mixed whirlers-- Sex differences in dancing--Time and periodicity of dancing--Influence of light on activity--Necessity for prolonged observation of behavior.
CHAPTER IV
BEHAVIOR: EQUILIBRATION AND DIZZINESS
Muscular coordination--Statements of Cyon and Zoth concerning behavior-- Control of movements, orientation, equilibration, movement on inclined surfaces, climbing--The tracks of the dancer--Absence of visual dizziness--Comparison of the behavior of the dancer with that of the common mouse when they are rotated in a cyclostat--Behavior of blinded dancers (Cyon, Alexander and Kreidl, Kishi)--Cyon's two types of dancer-- Phenomena of behavior for which structural bases are sought: dance movements; lack of response to sounds; deficiency in equilibrational ability; lack of visual and rotational dizziness.
CHAPTER V
STRUCTURAL PECULIARITIES AND BEHAVIOR
The functions of the ear--Structure of the ear of the dancer as described by Rawitz, by Panse, by Baginsky, by Alexander and Kreidl, and by Kishi-- Cyon's theory of the relation of the semicircular canals to space perception--Condition of the auditory organs--Condition of the equilibrational organs--Condition of the sound-transmitting organs--The bearing of the results of anatomical investigations upon the facts of behavior.
CHAPTER VI
THE SENSE OF HEARING
Experiments on hearing in the dancer made by Rawitz, by Panse, by Cyon, by Alexander and Kreidl, by Zoth, and by Kishi--Hearing and the voice-- Methods of testing sensitiveness to sounds--Results of tests with adults-- Importance of indirect method of experimentation--Results of tests with young--The period of auditory sensitiveness--Individual differences.
CHAPTER VII
THE SENSE OF SIGHT: BRIGHTNESS VISION
What is known concerning sight in the dancer--Brightness vision and color vision--Methods of testing brightness vision, the visual discrimination apparatus--Motives for discrimination and choice--Punishment versus reward as an incentive in animal experiments--Hunger as an incentive--An electric stimulus as an incentive--Conditions for brightness vision tests-- White-black vision--Evidence of preference--Check experiments--Conclusion.
CHAPTER VIII
THE SENSE OF SIGHT: BRIGHTNESS VISION (_Continued_)
The delicacy of brightness discrimination--Methods of testing the dancer's ability to detect slight differences in brightness--Results of tests with gray papers--Relation of intensity of visual stimuli to the threshold of discrimination--Weber's law apparatus and method of experimentation-- Results of Weber's law tests--Practice effects, the training of vision-- Description of the behavior of the dancer in the discrimination box experiments--Modes of choice: by affirmation; by negation; by comparison-- Evidence of indiscriminable visual conditions.
CHAPTER IX
THE SENSE OF SIGHT: COLOR VISION
Does the dancer see colors?--The food-box method of testing color vision-- Waugh's food-box method--Results of tests--Tests by the use of colored papers in the visual discrimination box--Yellow-red vision--Blue-orange vision--Brightness vision versus color vision--Brightness check tests--Green-blue vision--Violet-red vision--Conclusions.
CHAPTER X
THE SENSE OF SIGHT: COLOR VISION (_Continued_)
The use of color filters--Testing color vision by the use of transmitted light--Green-blue vision--Green-red vision--Blue-red vision--Stimulating value of different portions