W. J. V. OSTERHOUT 9 



the amount of a hypothetical salt compound (NaiXCa). This is 

 also true in the case of protoplasmic resistance, as shown in Fig. 3.^* 



It would therefore appear that we arrive at the same conclusions 

 whether we study net resistance or protoplasmic resistance. When 

 the solution is changed the constants change in a corresponding manner 

 in both cases, the only difference being in their absolute values, 

 but it is evident that in this case differences in absolute values are 

 of no importance. 



It should be emphasized that this general conclusion would remain 

 valid in case it should be found that the values given in this paper 

 for Cp and Cw are incorrect. There seems to be no doubt that the 

 value of Cw is constant under the conditions of these experiments 

 and as long as this is true the conclusions drawn from the study of 

 net resistance apply also to protoplasmic resistance. 



SUMMARY. 



An electrical current passing through a living plant flows partly 

 through the cell wall and partly through the protoplasm. The 

 relative amounts of these two portions of the current can be calculated. 



The outcome of such calculations shows that the conclusions drawn 

 from the study of the resistance of the tissue as a whole apply also 

 to the resistance of the protoplasm, and consequently to the permea- 

 bility of the protoplasm to ions. 



^*A rough calculation shows that this is also true of Kj^p and Kqp (corre- 

 sponding to the A'iv and Kq mentioned in the former paper'^). 



