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PLANTS UNDER MECHANICAL STIMULUS. 285 
condition than B (fig. 7a). It will now be found that a current 
of action flows in the stalk from A to B—that is to say, from the 
more excited to the less excited. When the B end is stimulated 
there will be a reverse current. The equal and opposite responses 
obtained by stimulating A and B are given in fig. 7 0}. 
We have in this method a great advantage over that of 
Fig. 74. 
Method of blocks 
Fig. 7 5. 
B 
Equal and opposite responses obtained by stimulating the ends A and B. 
negative variation, for we can always verify any set of results by 
making corroborative reversal experiments. ae 
By the method of injury again, one end is made initially 
abnormal, 7. e. different from the condition whic hit mainfans 
when intact. Further, inevitable changes will proceed un- 
