1909] OSTERHOUT—BEHAVIOR OF SODIUM AND POTASSIUM 99 
The most careful quantitative studies which we possess on this 
point are those of Miss Macowan.3 These studies show that the 
toxicity curves for K and Na are practically identical, while the cor- 
responding curve for Mg shows a much higher, and that for Ca a 
much lower degree of toxicity. 
ANTAGONISTIC ACTION* 
The antagonistic action of monovalent kations on each other has 
especial interest in view of the experiments of Lorss on Fundulus, 
which offer a certain analogy with those of LInDER and Picton.° In 
these experiments monovalent kations antagonized bivalent but did 
not antagonize other monovalent kations. | 
The curve of antagonism between NaCl and KCl shows two 
maxima. The location of these maxima, however, is not constant, 
but varies somewhat in different series of experiments. Table I 
and jig. show the average result of four series. The antagonism 
G H 
Fic. 1.—Antagonism curve, NaCl vs. KCl. The ordinates represent millimeters 
of sonh él the roots of wheat. The shies at A represents the growth in pure 
NaCl, that at P the growth in pure KCl. The other ordinates represent growth in 
mixtures of NaCl and KCl, the proportions of which are found opposite the corre- 
sponding letters in table I: thus the ordinate at H represents growth in a mixture o 
Toote NaCl+ rooce KCl. 
is comparatively slight. I have also noticed antagonism between 
Na and K in liverworts. 
Table II and jig. 2 show that both Na and K antagonize NH,, 
and that their effects are very similar. 
3 Ibid., 45:45. 1908. 
4 Cf. facts and literature hes by KEARNEY and CaMERON, Rept. No. 71, oa 
Dept. Agr. 1902; and by BENECKE, Ber. Deutsch. Bot. Gesells. 25:322- 1907- 
5 American Journal of a 3:327- Igoo. 
° Cf. HoBeR UND Gorpon, Hofmeister’s Beitr. Chem. Physiol. si Pathol. 5:432. 
1904. 
