CONTENTS XIX 



CHAPTER XXI 



DETERMINATION OF DIFFERENTIAL EXCITABILITY UNDER 

 ELECTRICAL STIMULATION 



PAGE 



Advantage of electrical stimulation, in its flexibility Drawbacks due to 

 fluctuating factors of polar effects, and counter polarisation-current 

 Difficulties overcome by employment of equi-alternating electric 

 shocks Methods of the After-effect and Direct-effect Experiment of 

 Von Fleischl on response of nerve Complications arising from use of 

 make and break shocks Rotating reverser Motor transformer Re- 

 sponse of Musa to equi-alternating shocks Abolition of this response by 

 chloroform Response records of plagiotropic Cucurbit a and Eel 

 Differential excitability of variegated leaves, demonstrated by electric 

 response ............ 272 



CHAPTER XXII 



RESPONSE OF ANIMAL AND VEGETAL SKINS 



Currents of rest and action Currents in animal skin Theories regarding 

 these Response of vegetal skin Stimulation by Rotary Mechanical 

 Stimulator Response of intact human skin Isolated responses of upper 

 and lower surfaces of specimens Resultant response brought about by 

 differential excitability of the two surfaces Differences of excitability 

 between two surfaces accounted for Response of animal and vegetal 

 skins not essentially different General formula for all types of response 

 of skin Response of skin to different forms of stimulation gives 

 similar results Response to equi-alternating electric shocks: (i) Method 

 of the After Effect ; (2) Method of Direct Effect Response of grape 

 skin Similar response of frog's skin Phasic variation of current of 

 rest induced as result of successive stimulation in (a) grape skin ; (b) frog's 

 skin; (c) pulvinus of Mimosa Phasic variation in autonomous me- 

 chanical response of Desmodium gyrans Autonomous variation of 

 current of rest True current of rest in skin from outer to inner This 

 may be reversed as an excitatory after-effect of preparation Electrical 

 response of skin of neck of tortoise Electrical response of skin of 

 tomato Normal response and positive after-effect Response of skin 

 of gecko Explanation of abnormal response 287 



CHAPTER XXIII 



RESPONSE OF EPITHELIUM AND GLANDS 



Epidermal, epithelial, and secreting membranes in plant tissues Natural 

 resting-current from epidermal to epithelial or secretory surfaces Current 

 of response from epithelial or secretory to epidermal surfaces Response 



a 2 



