The Demarcation Current of Mammalian Nerve. 323 



I. Experiment. Sciatic Nerve of Cat. 



Piece 5 cm. long. Difference of potential taken between the cross 

 section and a point 1 cm. distant. 



Volt. 



At once OO15 



After 25' in 9 per cent. NaCl solution at 17 C O'OOl 



Another 25' ., O'OOl 



Another 25' O'OOl 



Another 10' ., O'OOl 



After 15' in tap water at 17 C O011 



After another 30' in tap water at 1 7 C 0-022 



One hour and 40 minutes in the very " abnormal " saline solution of 

 9 per cent. NaCl and a subsequent 45 minutes in the very " abnormal " 

 saline solution of tap water, and yet the vigour of the changes is 

 unimpaired they are displayed to the same abnormal degree by the 

 effects of tap water upon the local circuit, and the contrasted states of 

 activity and hyperactivity are shown in exactly the same situations. 



II. Experiments upon Degenerated Nerve. 



In these experiments the preliminary operations for section of the 

 nerves were performed by Professor Sherrington, F.R.S. They are 

 described in the briefest possible manner, but as the nerves were made 

 the subject of systematic and detailed study the full description is 

 withheld, as in case of the other experiments, for an opportunity for 

 more detailed publication. 



Experiment a. Vagus of Dog. 



Preliminary Operation. 1 cm. of nerve excised at upper limit, and 

 1 cm. of nerve excised at the lower limit of the nerve in the neck. 



Examination nine days afterwards. 



Degenerated Nerve. 

 E.M.F. = 0-000 volt. 

 Several cross-sections were tried. 

 After an immersion of 25' in tap 



water 



E.M.F. = 0-017 volt. 



Intact vagus of other side. 

 E.M.F. = 0-006 volt. 



After an immersion of 25' in tap 



water 



E.M.F. = 0-016 volt. 



