i 4 4 RESPONSE IN THE LIVING AND NON-LIVING 



was found to be abolished. The depression produced is 

 so great and passes in so deep that I have often failed to 

 revive the response, even after rubbing the wire with 

 emery paper, by which the molecular layer on the sur- 

 face must have been removed. 



We have seen in the molecular model (fig. 62, d, e) 

 how the attainment of maximum is delayed,, the re- 

 sponse diminished, and the recovery prolonged or 

 arrested by increase of friction or reduction of mole- 

 cular mobility. 



It would appear as if the reagents which act as 

 poisons produced some kind of molecular arrest. The 

 following records seem to lend support to this view. 

 If the oxalic acid is applied in large quantities, the 

 abolition of response is complete. But on carefully 

 adding just the proper amount I find that the first 

 stimulus evokes a responsive electric twitch, which is 

 less than the normal, and the period of recovery is 

 very much prolonged from the normal one minute be- 

 fore, to five minutes after, the application of the reagent 

 (fig. 93, a). In another record the arrest is more pro- 

 nounced, i.e. there is now no recovery (fig. 93, b). Note 

 also that the maximum is attained much later. Stimuli 

 applied after the arrest produce no effect, as if the 

 molecular mechanism became, as it were, clogged or 

 locked up. 



In connection with this it is interesting to note that 

 the effect of veratrine poison on muscle is somewhat 

 similar. 'This reagent not only diminishes the excita- 

 bility, but causes a very great prolongation of the 

 period of recovery. 



