242 Mr. J. J. Woodward on the Modern 
quiescent muscles in these experiments exist also in uninjured 
animals hasnot remained unchallenged. Since 1867 it has been 
attacked especially by Hermann*, who has endeavoured to show 
that these currents are produced only under the special conditions 
of the experiments, and that there are in reality no natural 
muscle-currents at all. It was well known that the currents 
observed in the experiments varied greatly under different 
circumstances, and it seemed a significant fact that they should 
be most intense when the muscle was removed from the body 
and had both ends cut off. If the muscle was removed with 
its tendinous extremities still attached, the current was usually 
found to be very feeble or entirely absent, until the ends were 
well washed in salt and water or dipped in acid. Du Bois- 
Reymond had explained this by supposing the natural ends 
of the muscle to be protected by what he called a parelectro- 
nomic layer of positive elements that must be removed before 
the natural current could be made manifest. On the other 
hand, Hermann has endeavoured to show that the parts in- 
jured by the knife or acted on by the salt or acid enter at once 
into the well-known condition of rigor mortis, and only be- 
come negative to the still living portions of the muscle in 
consequence of this change. ‘That electrical disturbances 
actually occur in contracting muscles he admits, but endea- 
vours to show that they are due simply to the fact that the 
changes preceding contraction make the affected part of the 
muscle negative to every part less modified or wholly unal- 
tered. Hence if an uninjured muscle be caused, under proper 
precautions, to contract simultaneously in all its parts, it will 
be found that the contraction is wholly unaccompanied by any 
muscle-current f. 
Observations that appear to support these views of Her- 
mann have been brought forward by Engelmann f. On the 
other hand, Du Bois-Reymond has defended his views with 
vigour, and sharply criticized, of course, the labours and logic 
of his assailant §. I need not at present express any opinion 
as to the merits of this voluminous controversy. It is enough 
for my purpose to indicate the questions at issue as sufficiently 
important and uncertain to be well worthy of independent 
experimental criticism. 
Suppose, however, this criticism should result in showing 
* L. Hermann, ‘ Weitere Unters. zur Phys. der Muskeln und Nerven’ 
(Berlin, 1867) ; also Handb. der Phys. Bd. i. Th. 1 (Leipsic, 1879), 8, 192 
et seq. 
+ Hermann, Handb. der Phys. Bd. i. Th. 1, S. 216. 
} Engelmann, Pfliiger’s ‘ Archiv, Bd. xv. (1877), S. 116 e¢ seg. 
§ Du Bois-Reymond, Ges. Abhandl. Bd. ii. 8. 319 et seg. 
