374 



FLOYD JOHN BRINLEY. 



It will be noted from Table I. that the velocity constant for any 

 temperature is fairly consistent with the exception of 16, and 

 that K for the various temperatures is nearly constant. Plotting 

 the log of the rate against the reciprocal of the absolute tempera- 



60 

 50 



H4-0 



U 





 ct 



LJ 



30 



10 







-30 



'2 

 16 



10 2.0 30 4-0 60 60 

 MINUTES 



FIG. 6. Curve showing effect of temperature on the permeability of frog 

 skin to HCN. Internal and external pH 6.8. Temperatures used were 0, 

 16, 25, 30, 34.5 C. Abscissae represents exposure in minutes; ordinates 

 per cent, of total cyanide. 



ture, a curve was obtained as indicated in Fig. 7. The rate repre- 

 sents the time when the intracellular concentration of cyanide is 

 twenty-five per cent, of the external concentration. It will be 

 seen from this figure that there is a break in the line at 16 C. 

 (.003415). Calculating Q from the Vant Hoff-Arhenius equa- 

 tion, (26) 



K*/Ki = Q/2 



I T T 2 



a value of 11,179 is obtained at a temperature from 16 C. to 34.5 

 and 4,300 for o to 16. 



