214 



Mr. G-. J. Burch. On the Interpretation of [Feb. 11 T 



It is very important to note that a flat-topped curve may indicate 

 either that the wave of activity is so short compared with the distance 

 between the leads, that its end has completely passed the first lead 

 before its front has reached the second, or else, that the wave of 

 activity is so long, that both leads are for an appreciable time in- 

 cluded between its beginning and its end. 





























•O v. 



























—01 v. 









i 







*> 



r 



J- 





* 































•OO/js. -OOZs. -OOJs. -OOfs. 'OOSs. '006s. -OO/j. -OO^S. '009$. •OJO-i. '0//S. 'O/Xs. 



Fig. 13. — Effect of C0 2 on uninjured nerve kept 24 hours in tap-water saline 

 No. 1657 = normal response in air, T = 4 0, 78 C. K"o. 1663 = response after 

 CO : , T = 4°-73 C. Electrometer leads 1*6 cm. apart, exciting electrodes 1*4 

 cm. from the nearest lead. 



The most direct way of discriminating between the two cases is to 

 alter the distance between the leads. If, with the leads farther apart, 

 a sharper apex is produced, the wave is longer than from A to B. If, 

 on the contrary, the length of the flattened summit is increased, the 

 wave is shorter than the distance between the leads. An instance of 

 this is given in fig. 14. 



So far as the curves hitherto analysed have shown, both in kept 

 nerves, and in nerve under the influence of C0 2 , the length of the 

 wave is relatively less than in fresh uninjured nerve. That is to say, 

 the duration is not sufficiently increased to compensate for the slower 

 rate of propagation. 



In fig. 13 two analyses are given. One of these, No. 1657, is that 

 of a nerve response under normal conditions. The apex of the photo- 

 graphed curve was sharp, indicating that the length of the wave was 

 approximately equal to the distance between the electrodes, i.e., 1*6 cm. 

 The velocity of propagation, v, was 934 cm. per second. 



The curve of which No. 1663 was the analysis, taken during the 



