328 THE SO-CALLED SECONDARY ELECTROMOTIVE, ETC. 



couple of pages of elegant schematizing. Nothing is so elegant as 

 the simple truth. 



But is there a single subject in physiology to which more simple 

 and beautiful . explanations are applicable, even to the finest details, 

 than that of electro-physiology ? 



Four short, and more or less interdependent, propositions suffice 

 to explain all the galvanic phenomena, with the exception of the 

 shock of electrical fish and the ' action- currents ' of the retina, 

 neither of which are contradictory to them, although they may not 

 as yet, admit of explanation by them. These propositions are : 



1. Localised death in continuity of protoplasm, whether caused 

 by injury or by metamorphosis (mucous, horny), renders the dead 

 part negative electrically to the unaltered part. 



2. Localised excitation in continuity of protoplasm renders the 

 excited part negative electrically to the unaltered part. 



3. Localised warming in continuity of protoplasm renders the 

 warm part positive, localised cooling the cold part negative to the 

 unaltered part. 



4. Protoplasm is strongly polarisable on its limiting surfaces (first 

 shown as regards the protoplasm enclosed in tubes of muscles and 

 nerves) ; the polarisation constant decreases on excitation (and on 

 dying). 



Besides, having disposed of the secondary-electromotive pheno- 

 mena, the above investigation has furnished some not unimportant 

 contributions to the physiology of muscle and nerve. Pfliiger's 

 statements as to the movement of the indifference-point have been 

 verified for strong currents in a new manner, as well as the results 

 of Biedermann, of Engelmann, and of Van Loon as to the effect of 

 demarcation-currents upon the efficiency of ' physiological electrodes.' 

 The electrotonus of muscle intra- and extrapolar has been established 

 anew, and its complete analogy with the phenomena in nerve has 

 been shown, together with the quantitative differences as regards 

 its spread from the electrodes, especially from the anode. The 

 time relations of the electrotonic spread in nerve have been as 

 satisfactorily explained as the electrotonic after-currents. The 

 intimate connection of breaking tetanus with long persistent polari- 

 sation has been proved, and a new position in the investigation of 

 the nature of the breaking tetanus has been gained. 



In relation to many further questions new methods of experiment 

 have suggested themselves which will be better discussed when 

 these experiments are published. 



