viii CONTENTS 



PART III 

 THE CHIEF THEORIES OF COLOUR VISION 



SECTION I. GENERAL REVIEW. 



Chap. I. Introduction . 193 



Chap. II. Historical Review of Modern Theories of Colour Vision . 196 



SECTION II. THE DUPLICITY THEORY 203 



SECTION III. THE THREE-COMPONENTS THEORY (YOUNG-HELMHOLTZ). 



Chap. I. Statement of the Theory 213 



Chap. II. Researches based upon the Theory 



I. Normal Colour Vision 220 



II. Dichromatic Vision 232 



III. Anomalous Trichromatic Vision: Approximate 



Dichromatism ....... 235 



IV. Anomalous Trichromatic Vision : Shift of a Sensation 



Curve 243 



SECTION IV. THE OPPONENT COLOURS THEORY (HERING). 



Chap. I. Statement of the Theory 251 



Chap. II. Researches based upon the Theory 263 



SECTION V. OTHER THEORIES. 



I. Donders' Theory 270 



II. Ladd-Franklin's Theory 271 



III. McDougaU's Theory 274 



IV. Schenck's Theory 285 



V. Wundt's Photochemical Theory . . . .289 



VI. G. E. Miiller's Theory ... .290 



VII. Edridge-Green's Theory 291 



INDEX OF SUBJECTS . . . . . . 301 



INDEX OF AUTHORS .... . .... 305 



The Prismatic Spectrum of Sunlight, showing the positions of the chief 



Fraunhofer lines and wave-lengths ...... Frontispiece 



The author wishes to make grateful acknowledgment for permission to repro- 

 duce the following illustrations: 



to the Royal Society for Figs. 68 74 ; to the Royal Society and Messrs 

 Longmans, Green & Co. for Figs. 11, 12, 14, 1923, 2833, 40, 41, 49, 6165; 

 to the Kaiserliche Akademie der Wissenschaft of Vienna for Figs. 5, 60, 66 and 67 ; 

 to the proprietors of the Journal of Physiology for Figs. 2, 3 and 17, of the British 

 Journal of Psychology for Figs. 34 37, 42 and 43, of the Philosophical Magazine 

 for Figs. 38 and 39, of Mind for Fig. 75, and of the Zeitschrift fur Psychologie und 

 Physiologie der Sinnesorgane for Figs. 15, 16, 25 27, 45, 46 and 50 55; and to 

 Messrs Vieweg und Sohn, Braunschweig, for Figs. 1, 6, 7, 13 and 57. 



