LECTURE V 



The Discharge of an Electrical Organ in Response to Direct Excitation Du 

 Bois-Reymond's Summary Similarity between " Blaze-currents " of the 

 Skin and " Discharges " of an Electrical Organ Normal Direction 

 of the Organ-current A Speculation and some Experiments Further 

 Investigation of these Currents by the ABC Method The Positive 

 Polarisation of du Bois-Reymond The Polar After-currents of Hering 

 and of Biedermann Ritter's Tetanus and the Post-anodic Action 

 Currents. 



47. Electrical organs. We shall take a point of departure 

 from the diagram on p. 121 of the second paper by du Bois- 

 Reymond,* where he gives a summary of the effects of direct 

 electrical excitation of an excised portion of the electrical organ 

 of torpedo marmorata. 



The prefix "absolutely" in du Bois' terminology is used 

 with reference to the organ discharge, the response being 

 denoted as " absolutely positive " or " absolutely negative," 

 according as it is in the same direction as the normal discharge, 

 or of opposite direction. 



The prefix " relatively " refers to the direction of response 

 with reference to the exciting current, " relatively positive " and 

 " relatively negative " signifying that the response is in the same 

 and in the opposite direction to that of the exciting current. 

 If you are puzzled by these expressions, or doubt my 

 rendering of them, you should refer to the original paper. 

 Negative polarisation is of contrary direction to that of the 



* Archiv, 1885. 

 76 



