158 GENERAL PROPERTIES OF LIVING TISSUES 



Alter the angle by moving one electrode to 

 the right, the other to the left, and repeat the 

 experiment. 



The stimulating effect will increase as the 

 angle between current lines and the long axis of 

 muscular fibres diminishes. 



Nerves also are inexcitable to transverse cur- 

 rents. Differences in resistance play a great 

 part here. The resistance of nerves is said to 

 be 2|- million times that of mercury, when the 

 current passes along the nerve, and 12 J million 

 times when it passes transversely. 



THE INDUCED CURRENT 



The break induction current, owing to its rapid 

 rise from zero to maximum intensity, is a more 

 effective physiological stimulus than the make 

 current, and may therefore be chosen for 

 experimentation. 



1. The direction of the induction current in 

 the secondary coil is most easily determined 

 electrolytically. 



Arrange the inductorium for maximal currents. 

 Bring wires from the posts on the secondary coil 

 to a piece of filter paper wet with starch paste 

 containing iodide of potassium. Exclude the 

 make currents with the short-circuiting key ; 



