628 



COMPARATIVE ELECTRO-PHYSIOLOGY 



continuous transition, from abnormal positive to normal 

 negative, as before, through intermediate diphasic, with a 

 shifting of the base-line upwards, exhibiting an increasing 

 negativity. The gradual transformation of the character of 

 the response may be seen when a long series of successive 

 responses to successive stimuli is taken (cf. fig. 277). Or'the 

 abnormal positive may be seen transformed into normal 

 negative, after an intervening period of tetanisation (cf. 

 fig. 276). Or when the point of molecular transition is 



passed, the effect of intervening 

 tetanisation is to enhance the ampli- 

 tude of response (cf. fig. 275). It will 

 thus be seen that the characteristic 

 response in the sub-tonic condition A 

 is abnormal positive ; and that, when 

 the substance is transformed by 

 stimulation, to a point above the 

 transitional B, the response is con- 

 verted into normal negative, and 

 lastly, since the rate of transforma- 

 tion is very rapid above the point B, 

 that successive responses in that 

 region exhibit a staircase increase, 

 or moderate negative becomes the 

 enhanced negative, after an inter- 

 vening period of tetanisation. The 

 underlying transformation is thus 

 indicated by changes in the response, 

 and also by the shifting of the base- 

 line upwards, in exhibition of the characteristic curve. These 

 changes, which have now been described in the case of nerve, 

 will be found to apply in all other instances of molecular 

 transformation equally. 



Results in every way parallel are obtained with inorganic 

 substances. In fig. 384 is seen the abnormal electro-motive 

 response, represented as * down/ converted into normal 

 'up' after an intervening period of tetanisation. In the 



FIG. 384. Photographic Re- 

 cord showing Conversion 

 of Abnormal ' Down ' Re- 

 sponse in Tin to Normal 

 1 Up,' after Tetanisation 



