iv CONTENTS 



II. Experimental Work — (Continued) PAGE 



E. Tests with Changed Quality of Light 49 



a. Delayed response 50 



b. Peculiar behavior 52 



F. Tests with Energy Equated -. . . . 53 



G. Results of Experimenta IWork with use of Food Association 55 



H. Unlearned Responses of Fish 57 



a. Modified breathing rate of fish subjected to light of long 



wave-length 57 



b. Other characteristic behavior of fish in the presence of 



stimulus patches of unfamiliar light of long wave-length 58 



c. Dark adaptation and sensitivity to light 62 



III. REVIEW OF THE LITERATURE 63 



IV. DISCUSSION 78 



A. Analysis of Methods Employed 78 



a. Method of [response 78 



b. Method [of training 79 



c. Change of color in response 82 



B. Sou rces of Error 83 



a. From unsuitable environment or care 83 



b. From uncontrolled environmental factors 84 



c. From uncontrolled response 85 



d. From lack of training at matched brightness 85 



e. From exclusive use of the method of response 86 



C. General Considerations 86 



D. Final Statement of Results 89 



V. SUMMARY 92 



VI. CONCLUSIONS 99 



VII. POSTSCRIPT 100 



VIII. BIBLIOGRAPHY 104 



