DISSOCIATION OF COMPLEX SENSATION 



669 



responses being converted into short-lived positive, the 

 resultant sensation will become discrete and pleasurable 

 Before proceeding to describe these experiments in detail, it 

 will be well to present these inferences in the form of a 

 tabulated summary : 



EFFECT OF ELECTROTONUS ON INDIFFERENT SENSATION 

 IMPERFECTLY FUSED 



These generalisations I shall now demonstrate by means 

 of experiments carried out under, not one, but various forms 

 of stimulation. For experimental adjustment two conditions 

 have to be fulfilled. The first is so to regulate the intensity of 

 stimulus as to cause the indifferent sensation. The second 

 is so to adjust its frequency as to induce a fusion of effects 

 all but complete. It may here be pointed out that in general 

 the degree of frequency necessary to bring about this semi- 

 fusion will be a question of the effective intensity of 

 stimulation employed, and the excitability of the subject. 

 Having first decided on the intensity of stimulus to be 

 employed, it is easy to adjust its frequency by means of an 

 adjustable interrupter. 



I shall first describe the Sensimeter, by means of which 

 these experiments were carried out. Mechanical stimula- 

 tion, when required, was caused by a tapper, actuated by an 

 electro-magnetic arrangement (fig, 405). When an electrical 

 current is sent round the electro-magnet, the soft iron arma- 

 ture is pulled down against an antagonistic spring. When 

 the current is stopped the armature is released, and the 

 tapper delivers a blow. The height from which the tapper 

 falls determines the intensity of the blow, the former being 

 dependent on the strength of the electro-magnetic pull, 

 which is determined in its turn by the intensity of the 



