1902.] PhotograpJiic Records of the Response of Nerve. 215 



action of C0 2 , was flat-topped, indicating that the wave was shorter 

 than the distance between the leads. Unfortunately, an exact deter- 

 mination of the velocity was not possible, owing to the great changes 

 in the rate of development, /(tt). It may, however, be taken approxi- 

 mately as 467 cm. per second. This would imply a duration (6) of 

 0-001713 second in both cases. 



That is to say, the effect of C0 2 is to make the propagation rate 

 slower, and the E.M.F. both smaller and slower in development, but 

 not greatly to alter the duration of the maximum E.M,F. at any given 

 point. With regard to the last clause, however, I propose to obtain 

 more data. 



Fig. 14 is an interesting set of analyses. The nerve, with the 

 gastrocnemius attached, had been kept in tap-water saline for 20 

 hours. It was excited in the usual way, and the electrometer elec- 

 trodes were placed for the first experiment, No. 1532, 21 mm. apart. 

























+ 



•OZ *. 

























+ 



'OJ v. 





7 



A 



> 













































•O/ V-. 



>0 



0/3+ -0 



OX3. 'O 



c3s. *o 



043. -o 



063. *0 



063. 'O 



07s. -O 



Ofs. •mOOs. -O 



/OS. 







Fig-. 14. — Uninjured nerve, kept 20 hours in saline. T = 4°C. No. 1532, distance 

 between electrometer leads 21 cm. No. 1534, distance between leads 1*3 cm., 

 approximately equal to length of excitatory wave. No. 1535, distance between 

 leads - 65 cm. Telocity 1055 cm. per sec. Duration about 0*00123 sec. 



The proximal electrode was then moved 8 mm. nearer the distal, so 

 that they were 13 mm. apart in No. 1534, and 6 -5 mm. apart in 

 No. 1535. 



No. 1534 had a much sharper apex than either of the others, and 

 the analyses indicate that the distance between the electrodes was 

 greater than the length of the wave in 1532, and less in 1535. It may 



