Die Signalübermittlung im Nerven

Abstract

PROF. v. MURALT and his collaborators in Bern have taken up and developed the technique for the isolation of single frog‘s nerve fibres invented by the Japanese, Kato and Tasaki. As a result of optical and biochemical investigations of great technical ingenuity he has developed theories about the mechanism of conduction in nerve which might be described as unorthodox. The basic unit of conduction is supposed to be the internode of medullated nerve fibres, and v. Muralt believes that each is separated from the next internode by a transverse membrane at the node of Ranvier. Unfortunately his pictures do not provide decisive evidence of the existence of transverse membranes crossing the entire axon at the node. The optical appearances which they show are well known to histologists and are usually considered as representing the abrupt end of the myelin layer. His belief in the existence of this membrane was strengthened by the observation that in dying fibres it was sometimes seen to be blown out in the direction of one segment or the other. But the figure demonstrating this effect is not convincing and would be taken by most to show a modified portion of myelin rather than a membrane across the axon. However, the exact details of the node of Ranvier and the nature of the structure called by Cajal the cementing disk still remain very obscure, and v. Muralt‘s provocative study will certainly stimulate further investigation.

Die Signalübermittlung im Nerven

By Prof. Alexander v. Muralt. (Lehrbücher und Monographien aus dem Gebiete der Exakten Wissenschaften, Band 14: Reihe der experimentellen Biologie, Band 3.) Pp. 354. (Basel: Verlag Birk-häuser, n.d.) 38.50 Schw. francs.