698 COMPARATIVE ELECTRO-PHYSIOLOGY 



are by experimental results, account satisfactorily for the 

 particular electrical distribution in a muscle-cylinder. 



It is often supposed that dead tissue is negative to 

 living. But I have shown that this is not the case, the 

 dead being actually positive to the living. It has already 

 been mentioned, in connection with experiments described, 

 on the mechanical and electrical spasms of death, that at 

 the initiation of death, a tissue exhibits excitatory con- 

 traction and negativity, while the post-mortem effect is one 

 of relaxation and positivity. This explains the peculiar 

 electrical distribution which I have observed, in the explora- 

 tion of tissues, of which some parts were dead, others 

 dying, and still others, again, fully alive. It was there shown 

 (figs. 113, 115) that the greatest negativity occurred on the 

 death-frontier. Proceeding in either direction from this 

 point, whether towards the living or towards the dead, 

 it is found that these points are increasingly positive, or 

 decreasingly negative. But the maximum positivity of the 

 dead portion is greater than that of the living. From this 

 it is clear that the dead is positive to the living. 



From these facts, that the dying is negative, and the 

 dead relatively positive to the living, it is clear that the 

 so-called current of injury is liable to reversal. In the case 

 of the former, the current of injury will be from the 

 dying to the living ; in the latter, from the living to the 

 dead. This demonstration of the occurrence of a hitherto 

 unsuspected reversal, demonstrates to us the possibility of 

 many complications, and wrong theoretical inferences. For 

 response by the negative variation of the current of injury 

 is usually taken as the concomitant of the chemical process 

 of dissimilation, while the positive variation is held to be 

 associated with assimilation. Now, by the reversal of the 

 so-called current of injury, one identical excitatory reaction 

 may be made to appear, now as a negative, and again 

 as a positive variation. This is sufficient to indicate the 

 unreliability of the so-called Method of Negative Variation, 



