384 ELECTRO-PHYSIOLOGY CHAP. 



being served at different points by a plurality of nerve-fibres. The 

 theory that has recently found much support, from J. Geiiach in 

 particular, to the effect that there is no proper nerve-ending in 

 muscle, since the nerve as it enters passes over the contractile 

 substance in the whole extension of the muscle, ramifying every- 

 where between the elements of the muscle-fibre, in the form 

 of the finest varicose fibrils, must now be regarded as refuted, 

 the more so since it has been shown that Gerlach's nerve-fibrils 

 are really no more than the darkly-stained (gold chloride), and 

 therefore strongly -reducing, interfibrillar substance (sarcoplasm) 

 of the muscle. If the excitation thus starts, with indirect stimu- 

 lation, from the points of the fibre corresponding with the 

 nerve-ending, it must necessarily be transplanted thence in an un- 

 dulatory form on either side through the fibre. This is no mere 

 theoretical conclusion, but receives direct confirmation both from 

 histological investigation and from physiological experiment. As 

 regards the former, weighty evidence has recently been contributed 

 by Fottinger, Eollett, and others to the effect that the " fixed 

 wave of contraction " which is easily demonstrated in the muscle- 

 fibres of many insects, after proper treatment of the living tissue 

 with hardening and preserving fluids obtains mainly at the point 

 where the nerve enters, so much so indeed that the maximum of 

 contraction, i.e. the crest of the wave, usually falls in the centre 

 (sole) of Doyer's expansion. This, in addition to direct observation 

 of still living fibres, shows unequivocally that the entrance of 

 the nerve is the starting-point of an undulatory contraction pro- 

 pagated on either side through the muscle. 



The advance of the negative wave of excitation is demonstrated 

 with equal precision in the galvanometer, on indirect excitation 

 of the entire muscle, thus obviating the doubt expressed by du 

 Bois-Eeymond as to the undulatory nature of excitation, when the 

 muscle is stimulated from its nerve. The adductor magnus of the 

 frog is in all respects a suitable preparation, the nerve entering 

 by the centre of the muscle ; this muscle is a little more trouble- 

 some to prepare than the usual gastrocnemius and sciatic nerve- 

 muscle preparation, but the regularity and certainty of its results 

 are ample compensation. We may assume from the previous 

 experiments that such a preparation, on the excitation of its 

 nerve by induction shocks, will respond exactly like the muscle 

 excited directly at the nerve end-plate, in special cases, i.e., at the 



