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.E a i c . 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' a i c .C alc .. The fact that the receptive 

 excitability is heightened by this reagent, and conductivity 

 depressed, receives independent confirmation from the upset 

 of the balance, giving rise to a downward response. 



