XX COMPARATIVE ELECTRO-PHYSIOLOGY 



PAGE 



of Dillenia Response of water-melon Response of foot of snail The 

 so-called current of rest from glandular surface really due to injury 

 Misinterpretation arising from response by so-called ' positive variation ' 

 Natural current in intact foot of snail, and its variation on section 

 Response of intact human armpit Response of intact human lip 

 Lingual response in man Reversal of normal response under sub- 

 minimal or super-maximal stimulation Differential excitations of two 

 surfaces under different intensities of stimulus, with consequent changes 

 in direction of responsive currents, diagrammatically represented in 

 characteristic curves Records exhibiting responsive reversals >' . 312 



CHAPTER XXIV 



RESPONSE OF DIGESTIVE ORGANS 



Consideration of the functional peculiarities of the digestive organ Alter- 

 nating phases of secretion and absorption Relation between secretory 

 and contractile responses. Illustrated by (a) preparation of Mimosa ; 

 (b] glandular tentacle of Drosera General occurrence of contractile re- 

 sponse True current of rest in digestive organs Experiments on the 

 pitcher of Nepenthe Three definite types of response under different con- 

 ditions Negative and positive electrical responses, concomitant with 

 secretion and absorption Multiple responses due to strong stimulation 

 Response in glandular leaf of Drosera Normal negative response 

 reversed to positive under continuous stimulation Multiple response in 

 Drosera Response of frog's stomach to mechanical stimulation Re- 

 sponse of stomach of tortoise Response of stomach of gecko Multiple 

 response of frog's stomach, showing three stages negative, diphasic, 

 and positive Phasic variations . . . ... . . 329 



CHAPTER XXV 



ABSORPTION OF FOOD BY PLANT AND ASCENT OF SAP 



Parallelism between responsive reactions of root and digestive organ Alter- 

 nating phases of secretion and absorption Association of absorptive 

 process with ascent of sap Electrical response of young and old roots 

 Different phasic reactions, as in pitcher of A/epenthe Response to 

 chemical stimulation Different theories of ascent of sap Physical 

 versus excitatory theories Objections to excitatory theory Assumption 

 that wood dead unjustified Demonstration of excitatory electrical re- 

 sponse of sap-wood Strasburger's experiments on effect of poisons on 

 ascent of sap Current inference unjustified . . . . . 349 



