1922] GREAVES—SOIL 169 
bined. Later he (22) demonstrated that there exists, as measured 
by ammonification, a true antagonism between sodium chloride 
and sodium carbonate, and between sodium sulphate and sodium 
carbonate, thus indicating that the anions as well as the cations 
at times may play a part in antagonism. 
KELLEY (16), in studying the ammonification and nitrification 
of certain soils, found no antagonism between magnesium and 
sodium. LrpMAn and BurcEss (23), however, observed in the case 
of nitrogen fixation by Azotobacter chroococcum an antagonism 
between sodium and magnesium. 
WINSLow and FALK (39) have observed antagonistic effects in 
experiments on Bacillus coli. They found that cultures suspended 
in solutions of sodium chloride or calcium chloride were decreased 
in number, that higher concentrations produced sterilization of the 
culture, and that a combination of sodium chloride and calcium 
chloride in the molecular proportions of 5 to 1 was favorable to the 
growth of the organisms. 
SHEARER (29, 30) also demonstrated similar effects of salts 
upon the viability of Meningococcus and Bacillus coli. He found 
that a combination of sodium chloride and calcium chloride was 
favorable to growth, whereas each salt used separately retarded 
growth. 
Brooks (1) found that, as measured by the rate of respiration 
of Bacillus subtilis, there is a marked antagonism between sodium 
chloride and calcium chloride, and between potassium chloride 
and calcium chloride. The antagonism between sodium chloride 
and potassium chloride is slight, and the antagonism curve shows 
two maxima. Later, using the same method and organism, he 
(2) found a well marked antagonism between magnesium chloride 
and sodium chloride, and, contrary to the findings of Lipman (21), 
a very slight antagonism between magnesium and calcium. This 
isin keeping with my own (9) experience, which showed that a true 
antagonism exists between calcium sulphate vs. sodium carbonate, 
calcium sulphate vs. sodium nitrate, calcium sulphate vs. sodium 
sulphate, calcium sulphate vs. calcium chloride, calcium sulphate 2s. 
Magnesium sulphate, as measured in terms of ammonification. 
