CONTENTS XI 



Page 



charge of nerve impulses Polarization current Polar 

 fatigue Opening and closing tetanus Polar excitation 

 in injured muscle. 

 POLAR INHIBITION BY THE GALVANIC CURRENT . . . 153 



Heart Polar inhibition in veratrinized muscle. 

 STIMULATION AFFECTED BY THE FORM OF THE MUSCLE 156 

 EFFECT OF THE ANGLE AT WHICH THE CURRENT LINES 



CUT THE MUSCLE FIBRES 157 



THE INDUCED CURRENT 158 



V 



CHEMICAL AND MECHANICAL STIMULATION 



CHEMICAL STIMULATION 163 



Effect of distilled water Strong saline solutions Dry- 

 ing "Normal saline" Importance of calcium 

 Constant chemical stimulation may cause periodic 

 contraction. 



MECHANICAL STIMULATION 166 



Idio-muscular contraction.] 



VI 



IRRITABILITY AND CONDUCTIVITY 



IRRITABILITY AND CONDUCTIVITY 168 



Independent irritability of muscle Irritability and con- 

 ductivity are separate properties of nerve Minimal and 

 maximal stimuli; threshold value Summation of in- 

 adequate single stimuli Relative excitability of flexor 

 and extensor nerve fibres ; Ritter-Rollett phenomenon 

 Specific irritability of nerve greater than that of muscle 

 Irritability at different points of same nerve Excitation 

 wave remains in muscle or nerve fibre in which it starts 

 'Same nerve fibre may conduct impulses both centrip- 

 etally and centrifugally Speed of nerve impulse. 



