RESPONSES OF YOUNG TOADS 197 



sisting of ten trials. There were 736 responses toward the red 

 and 464 toward the blue. The following quotation gives a brief 

 statement regarding the experiments (I.e.): 



"Da Rot, trotzdem es heller als Blau war, in 30 Fallen 26mal starker 

 als letzteres besucht wurde, unterliegt es wol keinem Zweifel, dass das- 

 selbe dem Frosch, ahnlich wie dem Triton, viel angenehmer als das 

 Blau ist. * * * 



"Als (Minimal)-Verhaltnis ergibt sich 



Rot 1 



2) = . 



Blaum. ult. 0.6 

 d. h. es kommen auf 10 Rot- durchschnittlich nur 6 Blau-Besuche." 



The results of Graber's experiments with Rana esculenta L., 

 according to Torelle (I.e., p. 487), 



"Can be explained only on the ground of a confusion arising as a result 

 of using so many frogs (forty) at the same time in one receptacle." 



As will be shown, Torelle (I.e., pp. 478, 479) obtained results 

 with frogs, Rana virescens virescens and Rana clamata, exposed 

 to the stimuli of red and blue lights both at the same time, 

 much at variance with those of Graber (I.e.). For experimental 

 purposes Torelle used a low, narrow box about 45 cm. in length 

 with a glass plate at each end. Red light was admitted at one 

 end of the box and blue at the other. The frog was then sub- 

 mitted to the influence of the two lights. The response toward 

 the blue light was immediate, the animal moving toward the 

 source of illumination. Frequently the frog remained with its 

 head against the glass and turned toward the light. Appar- 

 ently there was no movement on the part of the frogs toward 

 the red light. These results of Torelle 's with frogs are largely 

 in agreement with those of the writer with specimens of young 

 Bufo americanus, as they are also with the statements of Holmes 

 in regard to frogs. According to this author (1907, p. 349) 

 the blue and the violet rays are the most effective in producing 

 phototactic responses. When two lights are used, red and blue, 

 frogs collect near the blue light. 



The results of the writer with specimens of young Bufo amer- 

 icanus and those of Laurens (I.e., pp. 277-282) with Bufo 

 americanus and Bufo fowler i are in accord. He worked with 

 pairs of balanced colored lights and found that the toads reacted 

 by giving motor responses, either jumping toward or away from 

 the source of illumination. The animals also responded by 



