ning of response is earlier when the applicaticin of Na2CO3 is fresh. In the experiment whose record is given, the wire is held at one end, and successive uniform vibrations imparted to the wire as a whole at intervals of one minute by means of a torsion head at the other end. Owing to after-effect of previous applications of Na2CO3, the sensitiveness of A is at the beginning great, hence the resultant response at the commencement is positive or upward. Dilute solution of Na2CO3 is next applied to B. The response of B (down) begins earlier, and continues to grow
Fig. 74. Transformation from positive to negative through intermediate diphasic variation. Thick dots represent times of application of stimulus.
stronger and stronger. The response therefore shows a preliminary negative twitch of B followed by positive variation of A. The negative grows continuously. At the fifth response, the two components, negative and positive, of the double response become equal; after that, the negative becomes very prominent, the positive dwindling into a feeble and inconspicuous response.
