Studies in Permeability. 
I. The Exosmosis of Electrolytes as a Criterion of 
Antagonistic Ion-Action. 
BY 
WALTER STILES 
AND 
INGVAR J 0 RGENSEN. 
With fourteen Figures in the Text. 
OR a considerable time now attention has been directed to the subject 
1 of antagonistic ion-action in the absorption of substances by plants, 
and a number of workers have employed different methods for the investiga¬ 
tion of the question. Yet it becomes manifest, on reviewing the literature 
of the subject ( 24 ), that the methods employed are generally long and 
laborious, while the accuracy or general character of the results obtained is 
open to much criticism. This is especially true of the most favoured group 
of methods where the use of water-cultures is involved. The notorious 
variability of plants growing in water-cultures, which necessitates the deter¬ 
mination of the degree of accuracy of the results of the experiments (22), 
has never been taken into account in these researches, and so the correctness 
of the results is often very doubtful. The most interesting contribution to 
the subject from a theoretical point of view is that of Sziics ( 25 ), but his 
method, dependent upon the geotropic reaction of the seedling root and 
hypocotyl, although ingenious, is very laborious, and, as his results show, is 
not open to any great accuracy unless so many plants are under observation 
that the experiments become more laborious still. 
Osterhout, in introducing a method from physical chemistry in the use 
of electrical conductivity properties of plant tissue ( 15 ), made the method of 
attack easier. So far, however, the use of physico-chemical methods has 
been very limited, and in consequence very few aspects of the problem have 
been considered, and little analysis of what constitutes antagonism has been 
attempted. 
[Annals of Botany, Vol. XXIX. No. CXV. July, 1915.] 
