HELMHOLTZ IN KONIGSBERG 



structed a special myographion, in which a weight, 

 by centrifugal action, liberated a spring that set 

 free a simple mechanism by which a current pass- 

 ing through the primary coil of a small induction 

 machine was opened. The shock thus obtained from 

 the secondary coil passed instantaneously to the nerve, 

 the nervous impulse was generated at the point irri- 

 tated, the impulse then travelled down the nerve, 

 and the muscle contracted, writing its curve on the 

 rotating drum. In this way two curves were traced 

 on the cylinder, one by contraction of the muscle 

 when the nerve was stimulated close to the muscle, 

 and the other when it was stimulated at a distance 

 from it. As the nerve, whether stimulated near or 

 far from the muscle, always received the induction 

 shock at the same moment when the cylinder had 

 attained its maximum velocity, the two curves did 

 not coincide at their commencement, the one corre- 

 sponding to the experiment in which the nerve 

 was stimulated at a distance being a little behind 

 the one produced when the nerve was stimulated 

 near the muscle. Thus during the time that 

 the nervous impulse was travelling, say along two 

 inches of nerve, the cylinder had travelled a short 

 distance farther on that is to say, had rotated round 

 its axis. The distance between the beginnings of 

 the two curves expressed the time occupied by the 

 nervous impulse in passing along a given length of 

 nerve. If the velocity of the cylinder had been 

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