Yerkes, The Sense of Hearing in Frogs. 



295 



according to the following method. Let the zero point on the 

 ordinates represent the value of the tactual reactions; then the 

 value of the auditory-tactual may be indicated on the same 

 ordinate as so many per cent, greater (above the zero point) or 

 less (below the zero point) than the tactual. In Fig. 5, for 

 instance, the sound when simultaneous with the touch caused a 



Fig. 5 Fig. 6 



Fig. J-. Reinforcement-inhibition curve for momentary auditory stimula- 

 tion, contracted on the basis of amount of reaction. Curve for male No. 



1 ; Curve for Male No. 3. 



Fig. 6. Reinforcement-inhibition curve for momentary auditory stimulation, 



constructed on the basis of amount of reaction. Curve for Female No. 



2 Curve for Female No. 4.^ 



'The curve for No. 4, Fig. 6, as originally published in Pft.i)ger's Archiv, Bd. 

 107, S. 219, is incorrect in that it starts with 50.7 (?^ instead of vi^ith 40.7 cjf,. 



