116 RESPONSE IN THE LIVING AND NON-LIVING 
carbonate then washed off, the increased sensitiveness 
conferred disappears gradually. Again, if we apply 
Na,CO,; solution to a fresh point, the sensitiveness 
gradually increases. There is another further interesting 
point to be noticed: the beginning of response is earlier 
when the application of Na,CO; is fresh. 
We have thus a wire held at one end, and successive 
uniform vibrations at intervals of one minute imparted 
Fic. 68.—Contrnvovus TRANSFORMATION FROM NEGATIVE TO PosITIVE 
THROUGH INTERMEDIATE DieHasic RESPONSE 
Thick dots represent the times of application of successive stimuli. 
to the wire as a whole, by means of a vibration head 
on the other end. 
Owing to the after-effect of previous application 
of Na,CO, the sensitiveness of B is at the beginning 
ereat, hence the three resultant responses at the be- 
ginning are negative or downward. 
Dilute solution of Na,OO; is next applied to A. The 
response of A (up) begins earlier and continues to grow 
stronger and stronger. Hence, after this application, 
the response shows a preliminary positive twitch of A 
followed by negative deflection of B. The positive grows 
