58 BULLETIN OF THE 



contraction moves along the muscle, which it does, according to the 

 observations of Bernstein and Hermann, 13 with a velocity of about 

 3 metres per second, it is preceded by a wave of negative varia- 

 tion. This negative variation is indeed so trifling, if the muscle 

 contracts but once, that it is difficult to observe it ; but when the 

 contractions succeed each other with great rapidity, as in artificially 

 produced tetanus, it may become sufficient to neutralize completely 

 the deflection of the galvanometer due to the current of the quies- 

 cent muscle. 



But the belief that the electrical currents, shown to exist in the 

 quiescent muscles in these experiments, exist also in uninjured ani- 

 mals has not remained unchallenged. Since 1867 it has been 

 attacked especially by Hermann, 14 who has endeavored 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 en- 

 tirely absent, until the ends were well washed in salt and water, or 

 dipped in acid. Du Bois-Reymond had explained this by sup- 

 posing the natural ends of the muscle to be protected by what he 

 called a parelectronomic layer of positive elements that must be 

 removed before the natural current could be made manifest. On the 

 other hand, Hermann has endeavored to show that the parts injured 

 by the knife, or acted on by the salt or acid, enter at once into the 

 well-known condition of rigor mortis, and only become 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 endeavors 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 pre- 

 cautions, to contract simultaneously in all its parts, it will be found 

 that the contraction is wholly unaccompanied by any muscle-cur- 

 rent. 15 



Observations that appear to support these views of Hermann 

 have been brought forward by Englemann. 16 On the other hand 



