212 Mr. G. J. Burch. On the Interpretation of [Feb. 11, 



Unless, therefore, it can be shown that these functions vary so as 

 to preserve the same relative values at different temperatures, the apex 

 cannot be used for this determination on a single set of observations. 























4 



•O/ 









.o- 



\* 

















•O 1r. * 

























- •O/V-. 



































•OO/a. 'OOZa. •Oo3a. -oafs. -ooSa. -Oo6a. -ooja. -OoSa. 'OOps. -O/Os. -0//s. •O/Zs. 



Fig. 12. — Influence of temperature on the response of a freshly prepared uninjured 

 nerve. Electrometer leads 1 cm. apart, exciting electrodes 1"5 cm. from the 

 nearest lead. 



It should be noted that this method will not serve if the nerve is 

 excited from the proximal end, because then / (q) comes in. 



If, however, the nerve is excited at two fixed points in succession at 

 each temperature, keeping A and B constant, the effect of / (x), / (0), 

 and/(&) will be eliminated from the result, and only the function 

 representing velocity of propagation will remain. 



Functions affecting the Form of the Curve. 



In the photographic records the total P.D. between the leads is 

 given by 



E = ccl + (3.dr/d6, 



where I = r - E is the distance of the meniscus from its zero 

 position B,. 



In the derived curves the values of E are plotted as ordinates with 

 the corresponding values of time as abscissa. Hence 



dE/dt = p.dh/dd -. 



But by the preceding investigation it has been shown that, for the 

 first phase, 



dE _ . I dp d-u dq\ 

 dt ~ f \dt' dt' dtj' 



