26 K. S. LASHLEY 



to wave-length as compared to brightness offers the possibility 

 of field and experimental studies of these much discussed 

 questions where the experimenter may feel reasonably confident 

 that his results are due to color perception. 



The conclusion of Katz and Revesz that the Purkinje phe- 

 nomenon cannot be explained by the process of adaptation in 

 the rods does not seem to be justified since neither the Purkinje 

 phenomenon nor the absence of visual purple has been estab- 

 lished for birds. It seems too early yet for a satisfactory corre- 

 lation of structure and function. Further studies of adaptation 

 upon birds with different retinal composition will doubtless help 

 to clear up the question of the function of the retinal elements. 



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1907. Arch. /.. Augenheilk., 57, 298-316. 



1907. Untersuchungen liber den Lichtsinn und Farbensinn bei Tagvogeln. 



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1908. Untersuchungen tiber das Sehen und tiber die Pupillenreaktion von 



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1904. Amer. Jour. Psych. 15, 248-271. 



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