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PHYSIOLOGY: IV. O. FENN 
SALT ANTAGONISM IN GELATINE 
By W. O Fenn 
LABORATORY OF PLANT PHYSIOLOGY. HARVARD UNIVERSITY 
Received by the Academy. July 28. 1916 
In studying the effects of electrolytes on living organisms Loeb^ 
has distinguished two groups of salt antagonisms. To the first belongs 
the antagonism between NaCl and CaCl2. Here the antagonism is 
between a monovalent salt and a salt with a strong (bivalent or tri- 
valent) cation. The antagonistic effect increases with the valence of 
the cation. To the second group belongs the inhibition of the toxic 
action of KCl on the eggs of Fundulus by means of sodium salts, the 
sulphate and citrate being the most effective. In this second group 
the antagonism is between a monovalent salt and a salt with a strong 
(bivalent or trivalent) anion, the effect increasing with the valence of 
the anion. 
A recent explanation of the first kind of antagonism has been presented 
by Clowes,^ who assumes that NaCl has a more strongly adsorbed anion 
and is therefore able to antagonize more strongly adsorbed cations (like 
Ca). His general conclusion is that electrolytes with a more strongly 
adsorbed anion are able to antagonize electrolytes with a more strongly 
adsorbed cation. No explanation is given of antagonism between 
monovalent salts and salts with strong anions (like Na2S04). 
From experiments on gelatine the writer has formulated a hypo- 
thesis by which both groups of antagonism may be explained. Accord- 
ing to this hypothesis (in many respects similar to that of Clowes) 
electrolytes with a more strongly adsorbed cation should antagonize 
electrolytes with a more strongly adsorbed anion, and in the case of salts 
like NaCl, the effect of the Na ion should predominate in the presence of 
strong anions and the effect of the CI ion should predominate in the pres- 
ence of strong cations. 
In agreement with this hypothesis it is found possible to duplicate 
experimentally both groups of antagonism, as defined by Loeb, i.e., 
NaCl is found to antagonize both anions and cations. This is not only 
in agreement with biological results, but it also correlates the well 
known fact that NaCl tends to maintain the neutrality of protein 
sols to which either acid or alkali have been added,^ and to decrease 
the viscosity of both alike. ^ 
The results of the gelatine experiments in so far as they concern 
antagonism are represented more completely in figure 1 in diagrammatic 
