THE INJURY CURRENT OF NERVE 339 
The concentration of the solution, therefore, which is indicated by this result as 
likely to annul the injury current, is "91 gramme molecule (dissociated) per litre of 
potassium chloride, that is a solution of approximately 10 grammes per cent, of KC1. 
Contrast such a result, which is in complete agreement with those obtained from 
the majority of the examples previously given, with the conclusion to be derived from 
an examination of the ' concentration law ' for a range of extremely dilute solutions, 
•2 grammes per cent. KC1, etc. There, judging from the example given on page 332, 
the ' concentration law ' is 
Ew = Ea log. 16 
n = tV x -94 
.-. Ew = Ea log. -32 
n 
The concentration of the annulling solution here indicated is "37 gramme molecules 
(dissociated) per litre of potassium chloride, that is a solution of approximately 3*5 
grammes per cent of KC1. 
Why should a nerve, which has been immersed for five minutes in an almost 
'isotonic' solution, be so repeatedly drawn into prophecying the annihilation of this 
phenomenon of the injury current as the result of an immersion of similar duration 
in 10 grammes per cent. KC1, and a reversal of the phenomenon as the result of 
immersion in solutions stronger than this : whereas a nerve which has been immersed 
for five minutes in a very dilute solution, far below the concentration of the isotonic 
solution, prophesies a similar doom for itself when less stringent measures are used 
against it, namely, when it is immersed in 4 grammes per cent. KC1 ? 
The answer, suggested by many facts exhibited in this research, and also by its 
absolute inherent probability, is that the reason is to be found in the removal of 
electrolytes from the nerve. A removal which has permanently diminished the value 
of the structures giving rise to the injury current, and 'weakened the nerve' by 
diluting the internal solutions of the axis cylinders. 
