On the distribution of chlorides in nerve cells and fibres

The question of the composition of nerve fibres, and especially of the axon itself, is one which must be solved before a rational explanation of the properties of nerve tissue can be given. The solution of the problem in its ultimate details is possible only when we have at our command reagents and methods which will greatly exceed in sensitiveness those which are accessible to us at present, for such as have been used hitherto comprehend only those of ordinary chemical analysis, and they have not thrown any light on the subject, while those of micro-chemistry, which have been employed up to the present, involve staining with dyes such as one employs in histological technique and treatment with nitrate of silver and osmic acid. The last-named reagent is of service in demonstrating the fat of the medullary sheath, and the nitrate of silver has been employed to show the nodes of Ranvier and the striation known as Frommann’s lines, a result which, as will be shown, depends on a micro-chemical reaction, but the dyes hitherto used have revealed little except structure. There are, indeed, the Weigert hæmatoxylin and the Golgi reactions, but the constituents of the sheath and axon responsible for both are unknown. Though these and other histological methods much has been ascertained regarding the structure of nerve fibres and cells, but so far little has been determined which will serve to explain such properties as irritability and conductivity and the nature of the nerve impulse itself. The result of investigations on the electrical properties of nerve fibres, however, show that the relationship between the electrolytic action of a current on the nerve and its exciting efficiency is a very intimate, practically an indissoluble, one, and in view of this one asks on what constituent the electrolytic effect is exerted.