THE ELECTROMOTIVE PHENOMENA 291 



2. Place non-polarizable electrodes on the 

 longitudinal surface and cross-section of the 

 sartorius. Fasten the wires of the stimulating 

 electrodes in the binding posts of the non-polar- 

 izable electrodes. Drop the nerve of the nerve- 

 muscle preparation across the electrode points. 



The gastrocnernius will contract when the 

 nerve bridges the space from one electrode to 

 the other, and thus completes the circuit be- 

 tween the longitudinal surface and cross-section 

 of the sartorius. 



3. Place a little 0.6 per cent solution of sodium 

 chloride in a porcelain dish. Fasten one end of 

 the sartorius gently between two pieces of cork 

 in the jaws of the muscle clamp. Bring the 

 muscle over the saline solution. Make a fresh 

 clean cross-section, and lower the clamp on its 

 stand until the cross-section dips (not too far) 

 into the solution. 



The muscle will twitch. The twitch will pull 

 the end of the muscle out of the solution. When 

 the muscle relaxes, the contact between positive 

 longitudinal surface and negative cross-section 

 is once more made by the saline solution, the 

 current of rest flows from the point of higher to 

 'the point of lower potential, and again stimulates 

 the muscular tissue through which it passes. 

 Thus the muscle is stimulated by its own cur- 



