EFFECTS OF ELECTRICAL WAVES 489 



be weakened by the mirror, and in consequence contractions 

 do not occur. The explanation through the assumption of 

 electric waves would be that standing waves are formed, and 

 that a node exists at the mirror. It was a simple matter to 

 show that this explanation is wrong. The mirror needs only 

 to be moved away steadily in order to show that at every 

 other distance contractions again begin. If we were indeed 

 dealing with standing waves, periodic inhibitions of the con- 

 tractions should have occurred when the mirror was steadily 

 removed from the nerve-muscle preparations. 



In this experiment it is also possible to replace the 

 metallic mirror by a moist glass plate or by the experi- 

 menter himself. When he stands behind the muscle and 

 brings one hand near each one of the two free ends of the 

 preparation, the contractions can easily be inhibited. I 

 need scarcely mention that this form of demonstration is 

 especially ' ' impressive. ' ' 



3. The objection might now be raised against this expla- 

 nation that we ought to give a more modern representation 

 of the changes whiclf occur in the preparations in these 

 experiments. I am glad to fill in this gap in my first pub- 

 lication, since this gives me an opportunity to enter more 

 deeply into the chemical theory of electro-physiological 

 effects, which I have begun to discuss in two previous 

 papers. The question which is of importance to physiolo- 

 gists in this case is the following: What is changed in a 

 nerve-muscle preparation, or any other living substance, 

 when we say that it has a negative or a positive charge of 

 electricity, as has happened repeatedly in this paper? It fol- 

 lows, first of all, from Faraday's law governing conduction 

 in liquids, that electricity can be conducted in living matter 

 only through a migration of ions, since only the liquid 

 portions of a cell are conductors. Ostwald has drawn the 

 further conclusion from Faraday's law that static electricity 



