CHANGES IN THE ROD-VISUAL CELLS OF THE FROG 

 DUE TO THE ACTION OF LIGHT 



LESLIE B. AREY 



From (he Anntomicol Lalxiratonj of the Northwes em L'tiiversily Medical School^ 



TWO FIGURES 



CONTEXTS 



L rrcliiiiiiKiry 420 



2. Experimentation 434 



A. Influence of light on the position of the red rod nucleus 435 



B. Influence of light on the length of the rod myoid. Relative changes 



at center and periphery of retina 43(5 



a. Red rods 436 



b. Green rods 439 



C. Influence of light on the diameter of the red rod 440 



3. Summary 441 



4. References 442 



I'ln'.Ll.MlNAKV 



Whenov(M- tlic fcsiilts of cxiMM-iinontatioii u])()ii any ]);(iti('iilar 

 anhiial, or groiij) of animals, are at \'ariance with a well cstab- 

 HsIkhI canon, it is ilosiniblo that such results be sul^jectod to the 

 closest scnitiny possible before the existence of a deviation 

 from the generally accepted norm is admitted. The present 

 paper, which attempts to answer the following; quer>', is concerned 

 chiefly wdth the reexamination of a case of this kind — Query: 

 Are the photoviechanical responses of the insual rods of the frog 

 similar to those occurring in the retinas of other inrestigated verte- 

 brates? 



I^otli the rods and the cones of many vertebrates undergo 

 positional changes when subjected to photic or thermal stinni- 

 lation (Arey '15, '16). 



1 Contrilnition Xo. 3S. April 20, 1916. 



429 



