On the Relation between the Conduction-rate, the Fibre-diameter and the Internodal Distance of the Medullated Nerve Fibre

Since Gasser and Erlanger (3, 4) published their extensive experiments on the relationship between the conduction-rate and the diameter of the nerve fibre, there has been a large amount of work concerning this problem (Blair and Erlanger, 2; Zotter man, 15; Pumphrey and Young, 9; Hursh, 7; Gasser and Grundfest, 6 etc.). The method adopted by these investigators, except for Pumphrey and Young who studied on invertebrate's nerve fibres, consisted in analyzing the action potentials observed on the nerve trunk. Although these previous results seemed fully convincing, it seemed to us still worth while to re-examine this relationship on vertebrate's nerve fibres, since it is possible for us to record action currents of artificially isolated single nerve fibres and to measure the conduction-rate and the fibre-diameter directly on each fibre. In the preliminary experiments, we have investigated the relation between the strength of induction shocks and the shock-response interval. The relation between the threshold and the fibre-size was also investigated in this connection. We have further examined the relation between the internodal distance and the fibre-diameter on the bull frog's nerve fibre. The work described in this paper was done by Tasaki in collaboration with Ishii and Ito. But several other members of the Institute, especially Kano and Kobayashi, have aided in carrying out some part of the work. Maruhashi has also aided in preparing photographs. We express our deep gratitude for their assistance.