192 



PHYSIOLOGY OF MUSCLES AND NERVES, 



dinal section, and a c and b d are transverse sections 

 through the cross-section. The curved lines represent 

 the divertinof arches, and the arrows show the direction 

 of the currents ^Yhich are generated in these. No 

 currents are generated in arches 6, 7, or 8, for these 

 unite symmetrical points. 



Moreover, the rate at which the tension decreases 

 ill the longitudinal section is, not regular, but at a 

 gradually increasing speed from the equator to the 

 ends. If, therefore, we find these iso-electric curves, the 



Fig. 50. Curuents in a muscle-pkism. 



tensions of which differ by a definite amount, these, in 

 the centre of the muscle-prism, are at some distance 

 from each other, but gradually approach more closely 

 too-ether toward the edge of the cross-section. If the 

 tension prevailing at each point in one side of a longi- 

 tudinal section is represented by the height of a straight 

 line drawn at right angles to that side of the longitu- 

 dinal section, then the curve which unites the heads of 

 these lines is level at the centre of the longitudinal 

 section, but sinks rapidly down toward the edges of the 

 cross-section. A somewhat similar fact is observable on - 



