^588 



P8TCH0L0OT. 



motorwards, draws a current from tlie previous one, S^ from 

 S^ and S" from S^ Cell S^ having thus drained S", if S** 

 ever gets excited again, it tends to discharge into S^; whilst 



Fig. 89. 



S'' having drained S'', S^ later discharges into S*', etc., etc. 

 — all through the dotted lines. Let now the idea of the 

 letter A arise in the mind, or, in other words, let S" be 

 aroused : what happens ? A current runs from S" not only 

 into the motor cell M" tor pronouncing that letter, but also 

 into the cell S^ When, a moment later, the effect of M"'s 

 -discharge comes back by the afferent nerve and re-excites 

 S", this latter cell is inhibited from discharging again into 

 JM" and reproducing the 'j^rimordial motor circle' (which 



Fig. 



in this case would be the continued utterance of the letter 

 A), by the fact that the process in S'', already under head- 

 way and tending to discharge into its own motor associate 

 M^, is, under tJw existing conditions, the stronger drainage- 

 channel for S"'s excitement. The result is that M^ dis- 

 ciiarges and the letter B is pronounced ; whilst at the same 

 time S" receives some of S'''s overflow; and, a moment later 



