200 niYSIoI.oi.Y OF MIX'US AM) .NKKYKS. 



of one arm, tin- ivsulf is an immediate deflec- 

 tion of tin- multiplier, which indicates the presence of 



a ciinvnl ascending in the contracted arm from the 



o 



hand to the shoulder. If the muscles of tin- other arm 

 are contracted, a deflection occurs in the opposite direc- 

 tion. \Ye are, then-fore, ;ille by the mere power of tin- 

 will to generate an electric current and to set the mag- 

 netic needle in motion. 



Summing np all that has been said, it appears that, 

 during muscular contraction, the electric forces acting 

 in the muscle undergo a change which is independent 

 of the alteration of form in the muscle, and is con- 

 nected \vilh the fact of activity itself. As. during this 

 alteration, the current which may be exhibited in an 

 applied arch becomes weaker, the term negative-variar 

 tinii of Un' muscle-current has been applied to it. 



2. The negative variation of the muscle-current on 

 contraction, as described in the last paragraph, is a 

 proof of the fact that in the electric action of muscle 

 we have to do, not with an accidental physical pheno- 

 menon, but with an action very closely connected with 

 the essential physiological activities of muscle. It is 

 therefore worth while to trace an action of this sort 

 more accurately, as it may possibly aid in the explana- 

 tion of the act ivity of the muscle. 



It may. in the tirst place, be safely asserted that all 

 niUM-le.s of all animals, as far as they have at present 

 IK -eii examined, exhibit the same electric action. K\en 

 -moolh muscles art electrically in the same way; 

 though in that case the phenomena are less regular, 

 o\\ing to the lad that the fibres are not so regularly 



arrayed a- in striated muscle. Moreover, the electric 



activity of smooth muscles seems to be somewhat 



weaker. 



