178 INJUEY, RECOVERY, AND DEATH 



40% of the original and in the pure sulfate it has fallen 

 to about 25% of the original, while in the mixture com- 

 posed of equal volumes of the solution of each salt, the 

 resistance has fallen only to about 60%. If no antagon- 



NaCl 100% 

 MaCit 00% 



75% 

 25% 



50% 

 50% 



25% 

 75% 



100% 



FIG. 79. Increased toxicity shown by curves of the electrical resistance of Laminaria 

 ayardhii in NaCl 0.52 M, Na-citrate 0.58 M (approximate) and in mixtures of these (the 

 proportions, representing c.c. of the component solutions, are indicated on the abscissae. 

 Curve A, observed values, after an exposure of 15 minutes to the solution, Curve B values, 

 expected on the supposition that neither salt affects the action of the other (additive effect). 

 The increase of toxicity is measured by the vertical distance between the curves. All 

 readings were made at 23 C. or corrected to this temperature. Each observed point pre- 

 sents the average of 10 experiments: probable error of the mean less than 10% of the mean. 



ism were present, the resistance in the mixture should 

 drop to about 35% (additive effect). 



Fig. 78 shows the antagonism curves after various 

 intervals, using resistance for ordinates and salt propor- 

 tions as abscissae. Here the antagonism is clearly evident. 



Similar experiments with NaCl and Na-citrate, by 



