PHTSIOLOGT 17 



lowance for the latter part it seemed feasible to 

 determine to what extent ions entered the proto- 

 plasm and carried the current through it. 



In the case of Laminaria similar results are 

 obtained whether we use direct or alternating 

 current. But recent experiments on very large 

 (multinucleate) cells, carried out in my labora- 

 tory by Mr. Blinks, indicate that the resistance 

 of protoplasm to a direct current is very much 

 greater than to an alternating current. It there- 

 fore seems probable that the surface of the cell 

 acts as a condenser and transmits an alternating 

 current without actual passage of ions. But meas- 

 urements of resistance to an alternating current 

 may nevertheless be very useful in detecting 

 changes in permeability to ions. If the normal 

 cell exhibits a high resistance and if this is less- 

 ened by a toxic agent, it shows that its permea- 

 bility to ions has been increased. As a matter of 

 fact determinations of electrical resistance by the 

 means of alternating current show a progressive 

 increase of permeability during the process of 

 death and this is borne out by a variety of other 

 evidence, such as the increased permeability to 



