EFFEOTS 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 which 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 
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