PHYSIOLOGY: I LOEB 
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formulated in the tribal rites, wherein was set forth, with unmistakable 
clearness, to the people, the importance of the perpetuation of human 
life upon the earth, and, of the recognition, that the life-giving power 
of Vv^akonda is ever present in all things that surround man. 
THE MECHANISM OF ANTAGONISTIC SALT ACTION 
By Jacques Loeb 
ROCKEFELLER INSTITUTE FOR MEDICAL RESEARCH. NEW YORK 
Presented to the Academy, August 2, 1915 
1. The work on antagonistic salt action has shown that we must 
discriminate between two distinct groups of such phenomena. The 
first group is represented by the counteraction of the toxic effects of a 
salt with a univalent cation by a salt with a bivalent cation. I showed 
in 1901 that all salts with a univalent cation rapidly kill the newly fer- 
tiKzed eggs of the marine fish Fundulus when the concentration of these 
salts exceeds a certain limit, while the addition of a very small (though 
definite) quantity of a large number of salts with a bivalent cation pre- 
vents or retards this injurious action.^ Salts with bivalent anions had 
no such effect. The role of the valency of the cation in these phenomena 
of antagonism was unmistakable and was pointed out in the same 
papers as was also the relation to certain rules in the precipitation of 
colloids, but it was not possible to indicate an antagonistic action on 
colloids between salts with univalent and bivalent cations. I suggested 
later that the rapid death of the eggs in the salts with univalent cations 
was due to a diffusion of the salts into the eggs, while the addition of the 
salt with a bivalent cation prevents or retards this rapid diffusion,^ and 
this suggestion was supported by later experiments. 
It therefore appeared from these observations that the salts with 
monovalent cations increase the permeability of the membrane when 
their concentration exceeds a certain limit, and that the addition of a 
trace of a salt with a bivalent cation, e.g., CaCU, diminishes the per- 
meability. This idea received support in the floating experiment of 
the writer with Fundulus eggs^ and in Osterhout's experiments on the 
galvanic resistance of Laminaria in NaCl and CaCU solutions,"* 
The second group of antagonistic phenomena is represented by the 
following experiments. In 1911 Loeb and Wasteneys found that a 
KCl solution in the concentration in which this salt is contained in the 
sea water is toxic for the marine fish Fundulus, while the addition of 
NaCl in a definite ratio (17 molecules or more of NaCl to 1 molecule of 
KCl) annihilates the toxic effect of KCl. Na2S04 was about twice as 
