THE ELECTROMOTIVE PHENOMENA 307 



on one electrode and the longitudinal surface on 

 the other, and connect them through a short- 

 circuiting key with the electrometer. Lay the 

 nerve of B on muscle A. Place the nerve of A 

 on electrodes connected with the secondary coil 

 (the coil should be well over the primary). 

 Bring the meniscus into the field, and open the 

 short-circuiting key. Place the stroboscope, still 

 in the primary circuit, near the meniscus. Tet- 

 anize the nerve of A. 



Fig. 52. 



For each stimulus received from nerve A, 

 muscle A contracts ; the contractions are so fre- 

 quent that they fuse into tetanus. At each 

 contraction of A, its current of action stimulates 

 the nerve of B, and B also contracts. At each 

 contraction of B, the action current displaces 

 the meniscus, which falls therefore into very 

 rapid oscillation. Observe the meniscus through 

 the stroboscope. It will seem to be standing 

 still. 



