Antagonism between salts (ion antagonism)

Loeb's 1912 book The Mechanistic Conception of Life indexes salt poisoning, the antagonism of acids and salts, and the antagonism of three salts. It also lists the cooperative action of salts in causing impermeability of the egg membrane¹. The index gives the topics, not the findings. In The Organism as a Whole (1916) Loeb put the matter as a law. In the ocean, and in blood and lymph, the salts exist in a ratio at which they mutually offset the injury that one or several would do alone². He called this the law of physiologically balanced solutions. He took it to be the general expression of the effect of changes in salt constitution for marine or all aquatic organisms³.

Osterhout's 1922 monograph on injury, recovery and death treats antagonism as something to be plotted. Its list of figures includes growth of roots in toxic solutions, growth in mixtures of unequally toxic solutions, a solid model showing the forms of the antagonism curves, and the effect of dilutions on those curves⁴. For the seaweed Rhodymenia, Osterhout reported that color changes after injury tracked death. The relative rates of death in NaCl, CaCl2 and their mixtures matched the results from conductivity⁵. He took this as confirmation of the electrical method for measuring antagonism. Antagonism between NaCl and CaCl2 was also observed in frog skin⁵.

Lillie, in Protoplasmic Action and Nervous Action (1923), called the antagonism between Na salts and Ca salts of chief biological interest and apparently universal in living organisms⁶. He treated the question of mechanism as unsettled. Whether protein or lipoid components of the plasma membranes chiefly underlie the permeability changes behind toxic effects he called an open one⁷. He thought both probably play a part, with the evidence leaning toward lipoid soaps as the variable component and proteins as the stable framework⁷. He also cited Clowes, who produced salt antagonisms in oil-water emulsions by varying the proportions of Na and Ca soaps in the interfacial films⁸.

Mathews and colleagues (2022) made a dye buffer from Hank's Balanced Salt Solution with 20 mM HEPES at pH 7.4. They used it to stain cells with DiBAC4(3) for resting membrane potential⁹. The passage names the solution but does not say what balance means there. Loeb's 1916 definition rested on the mutual offsetting of injurious salts². The held passages do not discuss antagonism in the modern work.