172 



COMPARATIVE ELECTRO-PHYSIOLOGY 



is -oi 8 volt, that of the dead is -0233 volt. Hence the 

 dead tissue is here positive to the living, to the extent ot 

 '0053 v lt- 



We have seen that the prevailing idea is that the dead is 

 negative to the living. But from the results here shown, we 

 can see that this is not a complete statement of the case. 

 Since then the electro-motive variation, instead of showing a 



25 



o -z 



FIG. 115. Distribution of Electric Potential in Petiole of Nymphaa alba, 

 one end of which has been killed. 



The point of maximum negativity is taken as zero, distances to the left 

 or towards the dead taken as minus, to the right or living, as plus. 

 Ordinate represents potential difference in thousandths of a volt. 



progressive change from the living to the dead, exhibits a 

 maximum difference, followed by a reversal, it may be asked, 

 what is the reason of this anomaly ? 



Much light is thrown on this subject from the results 

 given by another line of inquiry, to be explained in detail in 

 Chapter XVI. It is there shown that the plant-tissue on the 

 first onset of death exhibits a sudden contraction, indicative 



