AMERICAN 
JOURNAL OF BOTANY 
Vol. V April, 1918 No. 4 
COPPER AND ZINC AS ANTAGONISTIC AGENTS TO THE 
"ALKALI" SALTS IN SOILS 
C. B. LiPMAN AND W. F. Gericke 
Since the appearance of Osterhout's pointed reply^ to Loew's 
criticism of the conception of antagonistic salt effects and physiologi- 
cally balanced solutions for plants, no one has seriously questioned the 
validity of accepting as well-founded the aforementioned conception. 
Indeed the antagonistic salt effect is now regarded as one of the estab- 
lished facts in plant physiology, as it has been in animal physiology 
since 1900, when Loeb^ first suggested the idea of the ion-pro teid com- 
pounds and the mechanism of toxic and antagonistic salt effects. 
In the large amount of work which has been accomplished on the 
antagonistic effects of salts during the last fifteen years, the heavy 
metals have received very little attention, while the alkali and alkali- 
earth metals have been tested out in a number of ways and with a 
variety of media. 
In the experiments on animals, which we have cited above, it was 
found by Loeb^ that for the development of the eggs of marine fish 
(Fundulus) in NaCl solution of the same osmotic pressure as sea water, 
copper and mercury were powerless to antagonize the toxic effects of 
common salt. Zinc and cobalt, on the other hand, manifested a 
marked antagonism to NaCl in the direction indicated, and lead, 
nickel, and uranium showed slight but definite antagonistic powers 
under similar circumstances. Experiments involving antagonistic 
1 Osterhout, W. J. V. The Nature of Balanced Solutions. Bot. Gaz. 47: 48. 
1909. 
2 Loeb, J. On lon-Proteid Compounds and their Role in the Mechanics of Life 
Phenomena. The Poisonous Character of a Pure NaCl Solution. Amer. Journ. 
Physiol. 3: 327. 1900. 
2 Loeb and Gies, Pfliiger's Arch. 93: 246. 1902. 
[The Journal for March (5: 105-150) was issued April 26, 191 8.] 
151 
