138 



COMPARATIVE ELECTRO-PHYSIOLOGY 



is different. Here, the constant absorption of the minimal 

 stimulatory dose would cause accumulation in the system, 

 and thus ultimately bring about the death of the plant. 



FIG. 96. Photographic Record showing the Depressing 

 Action of 5 per c-nt. HC1 Acid 



The effect of very dilute acids is often to induce an 

 enhancement of excitability, while strong solutions induce 

 depression and abolition. In fig. 96 is shown the depression 



FIG. 97, Photographic Record showing Effect of I per cent. KHO 

 Note the preliminary positive twitch at the fourth response after application. 



and abolition induced by the application of a 5 per cent, 

 solution of hydrochloric acid. 



In dealing with the question of electrical response, we 

 have seen that two opposed electrical effects occur in the 



