90 University of California Publications in Agricultural Sciences [Vol.3 



to be more toxic than NaCl alone, isotonic with sea water (2.7 per 

 cent NaCl in sea water or about .4M NaCl). 



(c) Bacteria. — Lipman 23 with Bacillus subtil is obtained a result 

 similar to that of Osterhont. A mixture of the same concentration 

 of MgCL, and XaCl (.35M) in the ratios of 10:1 gave the maximum 

 production of ammonia. 



To summarize the results of these experiments, it may be said 

 that there is a distinct antagonism between MgCL and NaCl, which 

 is evident on both ends of the curves in figure 8. In this case the 

 yeast agrees with the observations on plants, animals and bacteria 

 except in the two instances cited above in regard to fresh-water 

 Grammarus and green algae. 



SERIES IX— ANTAGONISM BETWEEN POTASSIUM CHLORIDE AND 



SODIUM CHLORIDE 



In this series the flasks were arranged as before. It has been 

 pointed out by Loeb that two salts with ions of like valence, especially 

 in the case of monovalent ions, do not antagonize the toxicity of each 

 oilier, but rather show a moderately increased toxicity when com- 

 bined. This is evident with yeast, as is shown by table 9 and the 

 curves in figure 9. The highest growth in this case was found at F, 

 where .2M KC1 and .12M NaCl have been combined, having a ratio 

 of about 2:1. KC1 alone at ,2M concentration allows the growth 

 about iy 2 times that found in this combination. Thus the antag- 

 onism of NaCl for KC1 is found to be negative. But, on the other 

 hand, there is a distinct antagonism of KC1 for NaCl. For example, 

 NaCl alone at .17M concentration hardly allowed any growth, but in 

 combination with .01 M KC1 the growth was accelerated up to about 

 L5 millions, thus showing a distinct antagonism. The reason of this 

 unexpected negative result on the side of KC1 is perhaps the same 

 that I have suggested in the case of KC1 and CaCL in Series II. 



For comparison with these results, a number of cases dealing with 

 plants, animals and bacteria are cited below: 



(a) Plants. — Osterhout 22 with wheat (Early Genesee) has found 

 a slight antagonism between K and Na ions. But in his work 17 on 

 a green alga he obtained a negative result using 3/8M concentration 

 of two salts in combination. 



(b) Animals. — Loeb 1 with Fundulus found a slight antagonism 

 between the K and the Na ion in relation to the development of em- 



