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PROCEEDINGS OF THE AMERICAN ACADEMY. 



of each animal are shown, and it will he seen that the individuals often 

 vary widely in their different reactions. For example, toad No. 13 

 was negatively phototropic after being in the dark, but strongly posi- 

 tive after exposure to light. Although the effect of previous stimula- 



TABLE XII. 



Reactions of Individual Toads previously in the Light 

 or in the Dark. 



tion is marked in some individuals, yet when we consider the total 

 number of reactions, almost the same percentage of positive photo- 

 tropism is shown after prolonged exposure to the light as after a similar 

 period in the dark. These results agree with those of Torelle ( : 03), who 

 found that eight hours of exposure to light did not change the positive 

 phototropism of the frog. 



Table XIII. shows the times which elapsed before the reactions 

 recorded in Table XII. took place. No records were included which 



