ON THE MAMMALIAN NERVOUS SYSTEM. 



375 



Since the electrical changes evoked by excitation of the cord thus appeared to afford 

 true indications of the passage of nerve impulses along its nerve fibres, it seemed to 

 us quite possible to obtain for any one set of fibres a measurement of the value of the 

 electrical effects in it which would bear comparison with a similar measurement 



Cat. 



Adult 



! XIII. D 



REC TUS 



iv L 



obtained in the case of some other set. By piecing together the information thus 

 obtained, and by varying the conditions in which the cord was placed, we hoped to 

 determine the comparative number or at least resistance of the channels along which 

 excitatory impulses are propagated from the excited to the observed area. Further, 

 by means of carefully planned interruptions, we hoped to ascertain how far such impulses 



