THE CONDUCTIVITY BALANCE 



495 



and responsivity. I shall now describe further experiments 

 by which the relative effects of alcohol are compared, as 

 between conductivity and receptivity, and as between recep- 

 tivity and responsivity. 



For the purposes of such a comparison, a new balancing 

 arrangement has to be employed (fig. 305). Here, two 

 electro-thermic stimulators 

 are in series, so that ex- 

 citations may be produced 

 at two different points 

 simultaneously. The gal- 

 vanometer contacts E' and 



R; 



FIG. 305. Diagrammatic Repre- 

 sentation of Experimental Ar- 

 rangement for Demonstration 

 of RECEPTIVITY versus CON- 

 DUCTIVITY, or of RECEPTIVITY 

 versus RESPONSIVITY 



s and s' are exciting thermal loops 

 in series ; R and R', the enclosed 

 receptive points ; c and c', con- 

 ducting arms ; E and E', the 

 responsive points. 



FIG. 306. RECEPTIVITY versus RESPON- 

 SIVITY under Alcohol 



Alcohol was applied at the receptive point 

 to the left R', and the responsive point 

 to the right E. The formula was 

 R'aic.Eak. The photographic record 

 shows the relative enhancement of 

 receptivity. 



E are made with two points intermediate between the stimu- 

 lators. The distance of one of the two stimulators is kept 

 constant, at, say, 2 cm. to the left of E', while the other is 

 moved nearer to, or further from, E, until a balance is obtained. 

 A i per cent, solution of alcohol is then applied to the left 

 receptive point, R', and the right conducting area, c, the 

 formula now being R' alc .C alc .. The fact that the receptive 

 excitability is heightened by this reagent, and conductivity 

 depressed, receives independent confirmation s from the upset 

 of the balance, giving rise to a downward response. 



