276 
THOMPSON YATES LABORATORIES REPORT 
difference. The only circumstance which can lead to the absence of an injury- 
current is the temporary equality (in essential particulars) of the two solutions. The 
circumstances which determine a final disappearance of the phenomenon are : — 
1 . The destruction of the physical characteristics of the tubular membranes. 
2. And the total removal of all electrolytes from both solutions by a pro- 
longed washing of the nerve in water. 
One other point is also worth attention. Some reason has been given for 
concluding that the internal solution of electrolytes is the more concentrated of the 
two. Granted the correctness of the view which is here taken as to the causation of 
the injury current, then these experiments with water are in confirmation of such an 
opinion. The fact that an increased dilution of the external solution leads to an increase 
of the phenomenon may be taken as confirmative of the opinion that the phenomenon is due to 
the comparative dilution of the external solution. 
The measurements of resistance given in the following experiments were undertaken as indices of 
the extent to which the immersion in water succeeded in washing electrolytes from the nerve. 
EXPERIMENT (TAP WATER) 
Vagus Nerve of Dog 
Piece of right vagus ten centimetres long. Removed immediately after death. The potential 
differences given were measured between the upper cross section and points upon the longitudinal surface. 
Points ( 1 ) (2) (3), etc., refer in each case to a point on the longitudinal surface distant 1,2, 3, etc., 
centimetres from the upper end of the nerve. Point (10), therefore, is the second cross section, and the 
difference between the two cross sections recorded under this heading is here as in the other experiments 
marked by an asterisk. 
Potential Differences 
Average Values 
•00296 
27-2 x 10— * D. 
■00328 
•00328 
32-6 
•00328 
33-8 
•00328 
3+-6 
•00328 
3+'6 
•00348 
35 -6 
•00336 
3+'8 
•00304 
30-8 
•00008 
*oo-8 
Point (1) 
•00248 
„ 00 
■00300 
» (3) 
•00324 
„ (+) 
•00348 
„ (5) 
■00364 
» (6) 
•00364 
» (7) 
•00364 
» (8) 
■00360 
„ (9) 
•00312 
„ (>°)* 
•00008 
Points marked thus * are in each case the second cross section. 
