NATURAL MUSCLE-CURRENT. 447 



The central part of the longitudinal surface of a piece of muscle 

 is then positive, compared with the central part of the extremities 

 or transverse sections. And between these parts, the equator and 

 poles of the muscle cylinder, where the difference is most marked, 

 are various gradations, so that any point near the equator is posi- 

 tive when compared with one near the poles. 



There is, then, a current passing through the substance of the 



FIG. 182. 



Diagram to illustrate the currents in muscle. (e) Equator, corresponds 

 to the centre of the muscle ; (p) Polar regions of cylinder, representing the 

 extremities of the muscle. The arrowheads show the direction of the sur- 

 face currents, and the thickness of lines indicates the strength of the currents. 

 (After Fick.) 



piece of muscle from both the transverse sections or extremities 

 of the muscle block to the middle of the longitudinal surface, 

 whether it be a cut surface (longitudinal section) or the natural 

 surface of the muscle. This is called the muscle-current, or some- 

 times natural muscle-current. 



If the cylinder in the accompanying figure be taken to repre- 

 sent a block of muscle, e would correspond to the equator, and p 

 to the poles, and the arrowheads show the direction of the cur- 





