35 ^ Stiles and y0rgensen.—Studies in Permeability. /. 
Series 3. In this series copper sulphate was again used as the external 
solution, and various strengths between and were employed. Living 
125 5000 F * ' 
plants of Vicia Faba were used in place of potato as described in the section 
dealing with methods. It will be observed, by comparing the curves repre¬ 
senting the results of the two series, that the bean roots behave in the same 
way as the potato tissue. 
Series 4. A series of measurements was made in which potato discs 
were immersed in various strengths of a solution of lithium chloride. The 
salt used was manufactured by Merck. The concentrations employed were 
as follows : ——> 
I2 >5 
N 
250 
N 
500' 
N 
N 
N 
Although the rise in con- 
1000 2000 5000 & 
ductivity of the solution was not so great as in the case when copper sulphate 
was used, the general result was the same (cf. Fig. 4). 
Series 5. If the exosmosis of electrolytes from living tissue indicated 
by the experiments described in the preceding series is caused by the 
formation from the plasma membrane of substances completely permeable 
to the electrolytes which diffuse out, it would seem possible that, if the rise 
of conductivity is regarded as a measure of the extent of exosmosis of 
electrolytes, we might have here a criterion of antagonism. For if another 
substance be added to the toxic one, the exosmosis produced by the latter 
will be reduced if there is any antagonistic action between the two ions, and 
if the added kation is one which of itself produces little exosmosis, the result 
should be that in the mixed solution the conductivity will increase at a slower 
