reversf:d polar effects in living tissues 215 



alone enable us to explain — tend to exhibit abnormal polar 

 effects. 



Summary 



Under high E.M.F. the normal polar excitation tends to 

 be reversed. In the A stage, both the anode and kathode 

 excite at make, and either kathode or anode at break ; in the 

 B stage — that is, with excessively high E.M.F. — it is the 

 anode which excites at make, and the kathode at break. 



The firefly under excitation exhibits glow-response. 

 Under moderate E.M.F. it shows normal polar effects. 

 Under a high E.M.F. it, like the plant, exhibits a reversal 

 of these polar effects. Under fatigue, or other tissue- 

 modification, normal oolar effects tend to undergo reversal. 



