PSYCHO-PHYSICS 211 



namely, that of contraction and fall of the leaf. The effects 

 of feeble and strong stimulus are therefore not merely 

 quantitatively different but qualitatively, being of different 

 signs, positive and negative. He obtained identical results 

 from his electric mode of investigation, feeble stimulus 

 causing a positive and strong stimulus a negative electric 

 change. 



Moderately feeble stimulation brings about an increase 

 of energy ; excessive stimulation, on the other hand, causes 

 a run-down of energy ; and between these extreme cases is 

 a long range of variation in which either may predominate. 

 But anything which raises the tonic condition is for the 

 well-being and health of the organism, and is associated 

 with positivity ; and so of course conversely. Of the two 

 tones of sensation the positive is associated with what may 

 be regarded as pleasant or not-painful, and the negative 

 with the unpleasant or the painful. Various experiments 

 lent support to this conclusion, at least in typical cases, 

 and with ' grounds of reconciliation to those who hold on 

 the one hand that the motor reaction is secondary to the 

 mental, and on the other that sensation is merely an accom- 

 paniment of movements reflexly induced/ in fact between 

 the common view and the Lange- James theory. 



That the different sensation-tones have their physical 

 concomitants of opposite characters is also supported 

 by Miinsterberg, who holds that ' the feeling of agree- 

 ableness is the mental accompaniment and the outcome 

 of reflexly-produced movements of extension, and disagree- 

 ableness of the movement of flexion/ An ordinary observer 

 is familiar with the expanded and rounded outline of the 

 kitten purring with delight under gentle caresses, and the 

 sudden change of its attitude and aspect in contraction and 

 flexion, with the accompanying jump, under a pinch or a 

 blow. 



Bose next employed his very delicate method of experi- 

 mentation to determine the characteristics of the nervous 



