It is now well recognized that certain inorganic ions play a most important part in the proper functioning of cells. Through the researches of Macallum1 and Macdonald2 it is known that potassium is present in the nerve-fibers and not in the nerve-cells, and that it was not until some change had taken place in the axis cylinder that potassium was liberated in an ionic state. It might be true, therefore, on the basis of these observations that in any disease with changes in the axis cylinders we might expect to find that the cerebrospinal fluid contained an increased amount of potassium.
Rosenheim3 asserted that in all cases of acute degenerative insanity in which the presence of cholin was demonstrated in the cerebrospinal fluid, potassium in relatively large amounts could, also, be found ; but in the cases in which cholin was absent, very little potassium was