216 



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



be taken that the length of the wave was approximately 13 mm. 

 The rate of propagation, v, was 1055 cm. per second, so that the 

 duration (6) was about 0-00123 cm. per second in this preparation. 



In fig. 15 a similar preparation was used, but the nerve had been 

 kept 48 hours. 



Fig. 15. — Influence of distance between leads on the time relations of the recorded 

 electromotive changes. Nerve kept 48 hours. No. 1064, T= 4°'5 C, leads 

 2'3 cm. apart; second excitation at 0-0103 sec. So. 1071, T = 4° C, leads 

 0'8 cm. apart ; second excitation at 0*01 sec. 



On this occasion the proximal electrode was fixed, and the distal 

 electrode was moved nearer to it, the distance between them being 

 23 mm. in No. 1064 (T = 4°*5 C), and 8 mm. in No. 1071. It will 

 be noticed that the curves in this case commence at the same time, 

 whereas in fig. 14, when the proximal electrode was moved, they 

 crossed the zero line together. The velocity, %\ is about 1000 cm. per 

 second, and the length of the wave about 2 cm., giving a duration 6 

 of about 0-002 second, during which the electrical activity of each part 

 in succession is at a maximum. 



From the analyses it would appear that the period of development, 

 / (tt), occupied 0-0005 second, and that of subsidence, / (k.ir) 0'0015 

 second, from which it may be inferred that this particular nerve would 

 have been incapable of the smallest electrical response to a second 

 stimulus during/ (tt) + 6 = 0-0005 second + 0'0020 second, and only 

 capable of a more or less feeble response during a farther period of 

 0-0015 second. 



But although after about 0*0040 second the nerve might respond 

 with full force, it by no means follows that a separate record would be 

 given by the electrometer, for if the distance between maximum 

 electro-negative of the first wave and maximum electro-positive of the 



