TENSION PHENOMENA OF LIVING ELEMENTS. 



of the cut surface. This produces an electric current through 

 the medium and surrounding tissue. The fact that the current 

 actually passes through adjacent cells is shown by a displacement 

 of their contained colloids, identical in appearance with the 

 displacement produced by the currents used in the abo\v experi- 

 ments. V-mec 1 apparently observed these changes but did not 

 correctly d< -< ribe or interpret them. 



The fact that an electric current on inert MM- make Cumulates 

 inu-cle .it the kathode, and the fact that the muscle -nrface is 

 ix mil. illy po-itive in relation to the interior (cut surface), prob- 

 ably indicates that stimulation is produced by a rapid depolari. 

 /ation df the muscle surface. 



It tlii- reasoning be applied to an individual contractile 

 element, \\e may assume that the current causes kations i<> leave 

 tin (HINT surface of the membrane, and other kation- to be 

 an i -at ltd i. ward the inner side of the membrane, and thus the 

 pnl.iri/ation disappears or may even be reversed. JUM how this 

 causes an increase in permeability of the membrane i- a matter 

 \\hich \\- \\ill leave to the future for discussion. 



1 1 ha- b -i -i) supposed that the stimulated region acts as kathode 

 it. tin- adjacent portions, and these in turn act as katlnli < to 

 tin in \t portions and so the stimulus is propagated. 



^i imnlai ii .11 of a part of the surface, causing it t > I eo >me nx >n- 

 pcinical.lt in ions, depolarizes the adjacent parts "f the -urlai e 

 n\\iii- tt> the fact that confined anions migrate through the 

 pcrmcablt n and neutrali/e the charge- t.| the kations on 



adjacent parts of the impermeable region (see Fig. i). 1 <>r ihi- 

 iva-oii the increase in permeability is propagated. 



I hi- e\|ilanation of the phenomenon in a single rleim-m hold- 



lor a ti ue made up of many elements provided tin -t are in 



contact, as illustrated by the accompanying Fig. 2. Thi- i- 



]in.babl\- the mechanism of propagation of the negative variation 



and "-tiniulus") in many plant and animal tis-ti> 



This mechanism accounts for the movement of the negative 

 variation over a -nrface. But it may be possible for this electric 

 change to jump from one element, to another not touching it. 

 The observation- on the current of injury, cited above, show that 



1 "Rci/li-itiini; u <1. rd/loitrrulrn Strukturen b. d. Pflanzen," Jena, 1901. 



