346 
THOMPSON YATES LABORATORIES REPORT 
There is, however, no evidence that the conductivity of the nerve is affected by 
injury other than such as is adequately explained by the destruction of ' membranes,' 
structures which are characterized by low specific conductivity. There is, therefore, no 
evidence of the addition of electrolytes to the internal solution, nor even of the 
addition of electrolytes to localized portions of this solution. There is, therefore, no 
evidence that secondary chemical change takes any part in the development of the 
injury current. 
There is, on the contrary, evidence that all the conductivity of nerve is adequately 
explained by the presence of its inorganic salts, and, therefore, that all the electrolytes 
of normal nerve are inorganic salts. The electrical phenomena of nerve, if such 
evidence is considered as conclusive, depends entirely upon the inorganic salts which 
it contains. 
J fit is proven that the injury current is due to a ' pre-existent' differential distri- 
bution of electrolytes, and that all the electrolytes it contains are its organic salts, 
then the injury current becomes disappointingly a guide to nothing more than the 
differential distribution of inorganic salts in the nerve. 
The disappointment is modified, however, when the extraordinary nature of the 
differential distribution, as indicated by this phenomemon, is realized. For the indi- 
cation it gives is, that there is to be found within the axis cylinders a solution of 
extraordinary concentration ; a possibility itself intrinsically of great interest. 
When such a discovery is considered solely from the point of view of the previously 
determined facts of the conductivity of nerve, and the secondary consequences of con- 
duction by a nerve (the electrotonic phenomena), then it appears at once as the 
necessary corollary to such facts. Indeed, the probable occurrence of such a differential 
distribution of electrical conductors within the nerve, as indicated by these facts, has 
often been considered, even if no definite limits have been given to the speculation. 
The results of other methods of investigation used by physiologists may be said to 
have determined the expectation of such a condition, which expectation these results 
have amply justified. 
When such a differential distribution is, however, considered from another side, 
there is a very grave difficulty in accepting its possibility. For such a concentrated 
solution placed within the cell of an osmometer, separated only by a semi-permeable 
membrane from the dilute ' normal saline,' would be found capable of giving rise to a 
pressure of many atmospheres inside the cell. There is no knowledge available to 
decide the possible magnitude of the strain, which the extremely minute capillary tubes, 
in which we may presume this solution lies, would stand ; but it is, in ignorance, 
inconceivable that they should stand such a strain as this. 
On the other hand, there is reason to believe that in such capillary tubes the 
expected osmotic pressure may not arise, although highly concentrated solutions are 
present. Thus, there is the fact that fibrillar structures may actually concentrate 
