Stiles and J0rgensen.—Studies in Permeability . I. 351 
For the sake of simplicity we may consider the system with which 
we have to deal, as consisting of the three following phases : 
Exterior Complex of colloidal Interior of the cell 
solution substances (membrane) (crystalloids + colloids). 
But the system may be much more complex ; for instance, although 
earlier the cell-wall was not supposed to be active in permeability pheno¬ 
mena, the recent investigations of Hansteen Cranner ( 5 ) suggest that this 
forms an essential part in the mechanism of exchange between the exterior 
and interior of the cell. 
Now the problems of antagonism and absorption in general resolve 
themselves into considerations of the kinetics of this system ; but of the 
condition of equilibrium between any two phases we know very little in any 
single case. 
Osterhout’s method of attacking the problems consists in examining 
tissue of a marine Alga, Laminaria saccharina , in various solutions having 
an electrical conductivity equal to that of sea-water. The conductivity of 
the tissue he regards as a measure of its permeability ( 17 , 21 ). But the 
quantity which Osterhout calls the conductivity of the tissue, is really 
a complex quantity to which all the three phases mentioned above con¬ 
tribute. Hober ( 7 , 8) has pointed out that conductivity, as measured by 
Kohlrausch’s method, gives no true idea of the ion concentration of such 
a system, as the inner phase only contributes to a slight extent to the total 
conductivity. When the conductivity increases in Osterhout’s experiments, 
he considers the increase to be due to the higher penetrating power of the 
ions owing to a change in permeability, but he neglects the necessary effect 
of this, the diffusion of electrolytes between the inner and external phases 
of the system. 1 We have elsewhere ( 23 ) pointed out the complex 
character of plant tissue in regard to electrical conductivity, and that 
a change of conductivity may be due to a variety of different causes. 2 
Osterhout’s method, moreover, in its present form, is applicable to so 
very few cases, adapted as it is to marine Algae only. In the case of higher 
plants difficulty arises on account of morphological structure—in many 
plant organs there are different forms of cells which quite possibly have 
different permeability properties. Thus in the stem an increase in con¬ 
ductivity of the tissue might be due to an increase in concentration of 
electrolytes in the vessels and tracheides, and have nothing to do, at any 
rate directly, with permeability of living cells. Also when fairly uniform 
1 Osterhout has never made clear what he regards as the actual changes taking place in his 
experiments, but he seems definitely to regard as incorrect the view that it is diffusion phenomena 
which are the cause of his results. 
. 2 It is interesting to note that systems of this kind have been examined by a different method by 
Beutner and Loeb (1, 2, 3, 10,11, 12) by measuring the electromotive forces manifested. But even 
if the bearing of this work to our subject is still somewhat obscure, it may prove of importance in 
investigations of absorption and permeability. 
