CHAP. XI. CONCLUDING EEMAEKS. 153 



needle in consequence of one of the surfaces of the 

 muscle separating from the electrode during the 

 contraction of the fibre, and so breaking the circuit ; 

 or Is there a sudden diminution in the electric 

 tension of the tissue, and so producing a decrease 

 in the muscular current ? Now we have some 

 evidence that there is a discharge of electric force 

 during muscular contraction, as shewn by the galva- 

 noscopic frog in Matteucoi's experiments; but we 

 have no evidence that the muscular current is in- 

 creased in these experiments during muscular con- 

 traction. The loss of force, the lowering of the 

 electric tension of the muscular tissue, which takes 

 places during contraction, is restored by nutrition''. 

 If we can detect the evolution of electric force 

 in the muscular tissue during muscular action, 

 surely we ought to be able to obtain some evidence 



'' According to the principles of the Conservation of Force, we 

 must endeavour to trace out in what manner the force in the 

 muscle is disposed of. We have heat developed during muscular 

 contraction, as shewn hy Beoquekel, and Bkesohet, and 

 Mattewoci. Carhonio acid is evolved during muscular con- 

 traction, as shewn hy Matteucoi in his experiments on mus- 

 cular respiration. Electric force is evolved during muscular 

 contraction, as has been proved by Matieuooi, and confirmed 

 by others, and also by some of my own experiments. It would 

 be, perhaps, erroneous to suppose, that the force is converted 

 into chemical action, as nutrition; nutrition is undoubtedly 

 increased during continued muscular exertion; but muscular 

 action — contraction — would appear to be the first act in this 

 series of events, and nutrition the second ; contraction may be 

 considered as the exhausting act, nutrition the restoring act, 

 in this process. 



