86 



PRACTICAL PHYSIOLOGY 



Thus the electrodes are transposed, anode becoming cathode 

 and cathode, anode. 



FIG. 94. Plan of the arrangement of the two alternative circuits. 



B. It may be used to pass the current through either of two 

 pairs of circuits. By removing the cross wires and connecting a 

 pair of electrodes to each end pair of terminals a current may be 

 passed through either the left-hand pair or the right-hand pair by 

 moving the bridge. In this case the instrument acts simply as a 

 two-way key (Fig. 94). 



