XXVI COMPARATIVE ELECTRO-PHYSIOLOGY 



CHAPTER XLI 



THE MOLECULAR THEORY OF EXCITATION AND ITS 

 TRANSMISSION 



. PAGE 



Two opposite responsive manifestations, negative and positive Such 

 opposite responses induced by polar effects of currents of different signs 

 Arbitrary nature of term ' excitatory ' Pro-excitatory and anti-excita- 

 tory agents Molecular distortion under magnetisation in magnetic sub- 

 stances Different forms of response under magnetic stimulation 

 Mechanical, magneto-metric, and electro-motive responses Uniform 

 magnetic responses Response exhibiting periodic groupings Ineffec- 

 tive stimulus made effective by repetition Response by resistivity- 

 variation Molecular model Response of inorganic substance to electric 

 radiation Effect of rise of temperature in hastening period of recovery 

 and diminishing amplitude of response Sign of response reversed under 

 feeble stimulation Conduction of magnetic excitation The Magnetic 

 Conductivity Balance Effect of A-tonus and K-tonus, on excitability 

 and conductivity Conducting path fashioned by stimulus Transmission 

 of excitation temporarily blocked in iron wire, as in conducting nerve 

 Artificial nerve-and-muscle preparation . . . V* . . . 587 



CHAPTER XLII 



MODIFICATION OF RESPONSE UNDER CYCLIC MOLECULAR 

 VARIATION 



Anomalies of response Explicable only from consideration of antecedent 

 molecular changes Continuous transformation from sub-tonic to hyper- 

 tonic conditions Two methods of inquiry, first by means of character- 

 istic curves, second by progressive change of response Abnormal re- 

 sponse characteristic generally of A or sub-tonic state Abnormal trans- 

 formed into normal, after transitional B state B state characterised by 

 staircase response Responses at c stage normal and uniform At stages 

 D and E responses undergo diminution and reversal Responsive pecu- 

 liarities seen during ascent of curve, repeated in reverse order during 

 descent All these peculiarities seen not only in living but also in in- 

 organic substances, under different methods of observation Elucidation 

 of effect of drugs Response modified by tonic condition and past 

 history ............ 615 



CHAPTER XLIII 



CERTAIN PSYCHO-PHYSIOLOGICAL PHENOMENA THE PHYSICAL 

 BASIS OF SENSATION 



Indications of stimulatory changes in nerve : I , Electrical ; 2, Mechanical 

 Transmission in both directions Stimulatory changes in motor and 



