ON THE MAMMALIAN NERVOUS SYSTEM. 



397 



electrical effects evoked by its stimulation are due to the propagation of impulses 

 along fibres which are confined to the column. 



This lesion was effected in three Cats on the left side, the results are seen in the 

 following table : 



ELECTRICAL Effect obtained in the Lumbar Cord by Excitation of Columns in the 

 Dorsal Region after intervening Section of Left Posterior Column. 



AVERAGE Effect obtained from Side of Section. 



AVERAGE of Effect obtained from Side Opposite Section. 



Lateral . . 

 Posterior . 



Minimal 

 stimulation. 



10-2 



61 



Maximal 

 stimulation. 



152 



164 



It will be noticed that with minimal stimulation the interruption occasioned by the 

 unilateral section is almost complete ; hence we conclude that 



(a-.) The stimulation must be localised to the column on which the electrodes are 

 placed ; 



(b.) The electrical effect in the lumbar cord, following excitation of one posterior 

 column, must be due to nerve impulses proceeding down channels confined to that 

 column ; 



