FLOYD JOHN BRINLEY. 



less molecules and more ions. Such a condition was found to 

 exist, as is evident from Fig. 13 where more stimulation and less 

 toxicity occurred under the alkaline conditions than in the acid 

 solutions. 



In Fig. 14 are plotted the results of a series of tests using a solu- 

 tion of HCN in Ringer's solution. The pH of Ringer's solution 

 was about 8.2 ; by the addition of HC1 the pH was changed to 



.01 - 



20 30 4-0 

 MINUTES 



FIG. 14. Curve showing the effect of the pH of a solution of HCN in 

 Ringer's solution. Exposure to cyanide represented by the time between 

 arrows. First ten minutes skin exposed to Ringer's solution alone. pH 

 values used were 6.4 and 8.2. Abscissae represents the exposure in minutes 

 and the ordinates the P.D. in volts. 



6.4. The same concentration of cyanide was used in each series 

 (M/250). The "cells" were placed in Ringer's solution for ten 

 minutes, then removed; one series was placed in a solution of 

 HCN in Ringer's solution at a pH of 6.4 and the other series at a 

 pH of 8.2. Potentiometer readings were taken every minute for 

 45 minutes. Again it is evident from Fig. 14, that there is greater 

 stimulation and less toxicity under alkaline than acid conditions. 

 In either case the initial stimulation was not as pronounced as in 

 the experiments when borax buffer solution was used. It is, how- 



