ELECTRICAL FORCES 85 



In the first place it is observed that 

 injury changes the electrical condition 

 of the cell. If injured and uninjured cells 

 are connected to a galvanometer by un- 

 polarizable electrodes a current flows 

 through the galvanometer from the nor- 

 mal to the injured cells. 



It would seem at first sight that this 

 might serve to distinguish a dead cell 

 from a living one. We find, however, 

 that in many cases the current ("current 

 of injury") which may be very noticeable 

 when the cell is first injured gradually 

 falls off and disappears after the cell is 

 entirely dead. We also find that in tis- 

 sues, such as muscle, which can be easily 

 excited to activity the behavior of active 

 cells (as compared with one in the resting 

 state) with respect to the current is very 

 much like that of an injured cell. The 

 current therefore seems to be due to a 

 disturbance in the cell, produced by stim- 

 ulation or by injury, rather than to 

 death. In order to use it as a test of life 

 we must injure or stimulate a part of the 



