ANTAGONISM 175 



Thus it was found that in the case of Rhodymenia it 

 required more Ca to antagonize Na than it did in the case 

 of Laminaria. It was also observed that in the case of 

 Rhodymenia (Fig. 76) the antagonism was not so great 

 as in Laminaria and this appears to be correlated with 

 the fact that less decrease of permeability is produced 

 by Ca in Rhodymenia. In other words, the effect 

 of such a substance as Ca upon permeability not 

 only indicates what substances it will antagonize but 

 also, to some degree at least, the amount of antagonism. 



It may be added that Rhodymenia affords an interest- 

 ing confirmation of the value of the electrical method 

 in measuring antagonism, since the plants begin to change 

 color soon after injury occurs. It was found that the 

 relative rates of death as indicated by color changes in 

 NaCl, CaClo, and the various mixtures, correspond with 

 the results obtained by determining conductivity. 



Antagonism between NaCl and CaCl 2 was also 

 observed in the case of frog skin. 44 



Shearer (1919) in an experiment on bacteria finds 

 that NaCl and KC1 decrease, and that CaCL increases 

 the resistance, but that a mixture of these (Ringer's 

 solution) in the proper proportions preserves the 

 normal resistance. 



Thus far, we have confined ourselves to the consid- 

 eration of antagonism among kations. Numerous cases 

 of this are known, but the search for similar relations 

 among anions has achieved little result. Some cases have 

 been described by Loeb 45 and Miss Moore (1901, 1902). 

 Lipman and his associates 46 have reported antagonistic 

 action of anions as the result of studies on bacteria in 



"Osterhout (1919, C). 



"Loeb, J. (1905, 1912, A, B) and literature there cited. 

 "Lipman, C. B. (1912-13, 1914). Lipman, C. B., and Burgess, P. 

 S. (1914, 1914-1915). 



