170 



PHYSIOLOGY OF MUSCLES AND NEKVES. 



and leave the body. If the body which is inserted is of 

 simple form, the separate lines of transmission may easily 

 be calculated from the form; in bodies of irrecrular 

 shape this is somewhat hard to do, but even in such 

 cavses it is possible to determine experimentally, not only 

 that the electricity distributes itself throughout the 

 body, but even the lines along which the separate cur- 

 rents pass. 



Taking a simple example, for instance, a thick cyl- 

 indrical rod, in wdiich the electricity passes in at the 



Fig. 40. Distribution of the currents in irregular conductors. 



surface of one end and out at the other, it is prhiia facie 

 probable that the lines simply traverse the length of 

 the rod parallel to its axis. We may in imagination 

 replace the rod by a bundle of wires, each of which will 

 in this case be . traversed by a portion of the whole 

 current. If one of these wires is cut, and its ends are 

 connected with the multiplier, it is evident that that 

 part of the current which traverses this wire must 

 pass to the multiplier and cause a deflection of the 

 needle. But even if the wire is not cut, but is con- 



