

1905. | The Structure and Function of Nerve Fibres. 329 
it, and have used it in the manner described by him. As a result of my 
observations of its action I am in a position to extend his observations and 
give to them an entirely different significance. Not only are certain nodes of 
Ranvier, and various unexplainable intermediate points affected in the 
manner described by him, but every site of injury, and amongst these the 
intermediate points alluded to must be reckoned, is similarly affected. The 
cut ends are affected in the same way, as are also points purposely injured in 
the length of the fibres—as by placing a hair across a bundle of fibres and 
compressing a limited section of each fibre. Teasing the nerve in normal 
saline and leaving the teased fibres for some time in this solution before the 
introduction of the precipitating reagent, allowing the injury-current some 
period of action, the precipitate is given a new and much more extended 
distribution. It follows, therefore, that a new interpretation must be placed 
upon these results. Since precipitates of potassium salts can be obtained at any 
point arbitrarily selected as the site of an wyury, these salts are, therefore, really 
present at every pont in the course of the nerve-fibre, and that too in astonishing 
quantity. The presence of these salts is only revealed where the axis-cylinder 1s 
involved in the process of injury. Further, an examination of such preparations 
gives no support to the idea, that these are situations to which the precipita- 
ting reagent has readier access. ‘The results are exactly comparable to those 
obtained with neutral-red. In the latter case there is no doubt of the fact, 
that the dye may be present in maximal quantity in long stretches of the 
fibres in which no such appearances are seen; indeed, it is frequently the 
case that such parts are more deeply stained than tracts in which there is a 
well-marked granular formation. 
This revelation of a strong solution of electrolytes at every injured point, 
and the successful concealment of a similar quantity of inorganic salts at 
every other point, seems worthy of the most serious consideration. It has 
long been supposed that the state present at an injured point was comparable 
to the transitory state of excitation involving normal points of the nerve. 
Let it be assumed, as it has often been assumed, that it is merely a more 
fatal and irrecoverable degree of the same kind of change, then the observa- 
tions of this state recorded above contain a sufficient explanation of the 
phenomena of nerve-conduction. It is better to take the pure phenomenon 
of nerve-conduction, the characteristic function of nerve, apart from a 
consideration of its outwardly recorded symptom, the action-current; for the 
latter cannot be considered without dealing with the permeability of the nodes 
of Ranvier, and the effect of this permeability upon the relative velocity of 
anions and kations traversing it. The picture of the process resulting from 
injury as observed above is as follows :— ne 
VOL. LXXVI.—B. Z 
