265 
Absorption of Salts by Plants. 
Conclusion. 
From this brief survey of the work published on antagonism it 
is evident that we are here dealing with a phenomenon of wide¬ 
spread or perhaps universal occurrence in organic life, as it as been 
observed in regard to absorption by both animals and plants, and 
in the case of the latter in regard to species from all parts of the 
plant kingdom. 
Antagonism appears to be limited to kations, 1 but not merely 
to those which are generally supposed to have a nutritive value or 
which are present in the plant, but, as Sziics’ researches have 
shown, it exists also between such unnecessary or poisonous ions as 
aluminium and copper, and even between metals and alkaloid bases. 
The cases of antagonism that have been observed so far appear 
to show that this effect is greatest between ions of a different 
valency, but it is not altogether absent between ions of the same 
valency. 
The most plausible explanation of antagonism that has been 
put forward is certainly that of Sziics, which is itself based on 
Pauli’s view of absorption. 
Pauli (32) regards the plasma-membrane as acting as a carrier 
of ions into the interior of the cell. The plasma-membrane is 
supposed to form compounds with the ions and by the reversibility 
of the process the ions enter the cell. 
Sziics points out that on this view it is possible to understand 
how it is that inorganic electrolytes which play so important a part 
in plant nutrition, but which on the other hand are insoluble in 
lipoids, 2 are able to enter the cell. 
Sziics concludes that on Pauli’s view, if there is outside the 
cell a mixture of salts containing two different ions, both of which 
are carried in by the same radicle of the plasma-membrane, these 
ions must naturally hinder one another’s absorption; each Will 
combine with a part of the plasma-membrane substance which 
would otherwise be used by the other ion if that alone were present, 
and so the absorption of both ions is hindered. 
T However an antagonism between anions has recently been recorded by 
Miyake (21). 
5 It should be noted that the theory of Quincke and Overton to the effect 
that the plasma-membrane is of the nature of a continuous film of lipoid, is by 
no means generally accepted, although most workers are agreed as to the 
presence of lipoid in the plasma membrane. Czapek (8) for instance suggests 
that the fatty substance might simply be suspended as an emulsion in a 
colloidal complex of water and proteid, which would enable one to understand 
the intake of substances like salts which are insoluble in lipoid but soluble in 
water. 
