462 L. V. HEILBRUNN. 



to be of greater moment than changes in the conductivity of the 

 cells themselves. The factors involved include possible changes 

 in the size and shape of the spaces between cells, as well as 

 changes in their conductivity. One such factor is perhaps of 

 especial importance for substances like the ordinary fat-solvent 

 anesthetics which alter the viscosity of the medium in which 

 they are dissolved. This is the effect of a change in the viscosity 

 of a solution on its conductivity. Concerning this effect Walker 

 (5) says: 'The addition of a small quantity of a substance such 

 as alcohol to water increases the viscosity of the water. Corre- 

 sponding to this increase we find that the rate of diffusion is less 

 when a substance is dissolved in water containing a little alcohol 

 than the rate of diffusion when water alone is the solvent, no 

 matter what the dissolved substance may be. Similarly the 

 speed of ions in water containing alcohol is less than their speed 

 in pure water." 



Let us consider some of Osterhout's experiments more closely. 

 He measured the conductivity of Laminaria in various solutions 

 of anesthetics and compared it with the conductivity of the 

 same material in sea-water. In one experiment he adds to 970 

 cc. sea-water 10 cc. of ether plus about 5 cc. of sea-water con- 

 centrated by evaporation until its conductivity was about double 

 that of ordinary sea-water. In another experiment he adds to 

 970 cc. sea- water 30 cc. of absolute alcohol plus 15 cc. of con- 

 centrated sea-water (apparently made up as before), thus 

 obtaining a 0.5 molecular solution of alcohol which he refers to 

 as 0.05 molecular. This solution, according to Osterhout, has 

 the same conductivity as sea-water. But this scarcely seems 

 possible. Osterhout's solution has approximately the same con- 

 centration of salts as sea-water, but the viscosity of the solution 

 is decidedly higher. Pissarjewsky and Karp (6) found that a 

 0.5 molecular concentration of alcohol lowers the conductivity 

 of normal NaCl solution until it is about 8 per cent, below that 

 of the conductivity of normal NaCl solution in pure water. On 

 the other hand, the ether solution used by Osterhout wou!d have, 

 as he claims, approximately the same conductivity as sea-water, 

 for Arrhenius (7) found that I per cent, ether lowers conductivity 

 only about 2 per cent, for various types of electrolytes. 



