and Plants to the Electrical Phenomena associated with it. 49 



state from the living structural elements on one side to those on the 

 other ; but if we compare the condition of the unexcited preparation 

 immediately before and after the application of the ligature, we find 

 evidence that breach of continuity of function is not the only effect 

 produced by it. If the one contact is placed on the ligatured part it 

 is found that, irrespectively of any excitation, there exists a large 

 difference of potential between the contacts, which may amount to 

 four or six hundredths of a volt. 



The Muscle Current. 



Now it is easy to prove that this difference is not due to breach of 

 continuity, for if you shove the electrode away from the ligature in 

 either direction it disappears. The phenomenon which is thus brought 

 to light is that to which the great founder of animal electricity, du 

 Bois-Eeymond, applied the term "muscle-current," and when the 

 method I have described is employed, it presents itself in its utmost 

 simplicity — for by the act of tightening the ligature previously applied 

 under an electrode, you at once bring into existence a state of things in 

 which the constricted part is negative to the living parts on either side. 



What happens in this case 1 What is the difference between the 

 state of the surface of contact immediately before and immediately 

 after the tightening of the ligature ? Nothing more can be said than 

 that a certain process which was going on there and which provisionally 

 Are call " life," being ignorant of its nature, has been annulled. What 

 we actually observe may be represented diagrammatically thus : — 



Diagram 5. 



The divided line represents the graduated wire of a potentiometer ; at d is a ligature 

 as yet not tightened round a muscle ; p and d are equipotential. The galvano- 

 meter is at zero and the slider of the potentiometer is up to the block. 

 The ligature is tightened ; at once the needle indicates a current directed from 

 d top, but can be brought by the slider again to zero. 

 VOL. LXV. E 



