THE ELECTROMOTIVE PHENOMENA 287 



II 



THE ELECTROMOTIVE PHENOMENA OF 

 MUSCLE AND NERVE 



THE stored energy of muscle is set free in molec- 

 ular movement, heat, chemical action, and 

 electricity, and in mechanical work, the change 

 in form. It will be convenient to consider the 

 electromotive phenomena first. 



THE DEMARCATION CURRENT OF MUSCLE 



Demarcation Current of Muscle. 1. Mount 

 two non-polarizable electrodes. Connect them 

 to the capillary electrometer through a short- 

 circuiting key. Kemove a sartorius muscle. Cut 

 off each end with a sharp knife by a clean cut at 

 right angles to the fibres. Observe that the 

 muscle is thereby converted into a " muscle 

 prism." It possesses two artificial cross-sections, 

 at each of which the muscle has been injured, 

 and is, in fact, dying, and an uninjured natural 

 longitudinal surface. Place the muscle across 

 the electrodes so that the cross-section rests on 

 one electrode and the middle of the longitudinal 

 surface rests on the other. Bring the meniscus 

 of the capillary into the field. Note its position 

 on the micrometer scale. Open the key. 



