Antitoxic Action of Certain Bases 165 



As contrasted with their independent action, the poisonous action of 

 sodium and ammonium ions is greatly decreased when present together in 

 solution. This holds when N/50 NaCl is combined with N/100 to N/1000 

 NH4CI, and also when N/1000 NH4CI is combined with N/100 to N/1000 

 NaCl. 



Barium ions are very toxic, the elongation of roots of pea seedlings 

 in N/4000 BaCl2 being only about two centimeters. These ions are 

 rendered innocuous by calcium, since growth of seedlings is not retarded 

 when placed in culture solutions composed of N/20 CaCl2 + N/250 BaCla- 



Magnesium and potassium ions also are fairly effective antidotes for 

 barium. On the other hand, barium is a powerful antidote for magnesium 

 and potassium. Thus, the toxicity of N/800 MgCl2 is prevented by 

 the presence of N/6000 BaCl2; the deleterious action of N/25 KCl is 

 overcome by N/2000 BaCU and N/1000 CaCls (N/1000 CaC]2 being 

 the solvent). 



Pure solutions of strontium, even when very dilute, retard the growth 

 of seedlings. Calcium, potassium, sodium, and magnesium each reduces 

 the deleterious action of strontium. Strontium, although present in 

 relatively high dilution, is effective in reducing the toxicity of either 

 potassium, sodium, or magnesium ions. 



Mutual antagonism results when potassium and sodium ions are present 

 together in solution. Greater development of seedlings takes place in a 

 solution composed of N/500 KCl + N/50 NaCl than in one composed 

 cf N/50 KCl + N/500 NaCl, thus showing that potassium is a more 

 effective antidote for sodium than sodium is for potassium. 



The results obtained from the studies of the influence of age of seedlings 

 on toxic and antitoxic action show in general that older seedlings are far 

 more resistant than younger ones to the toxicity of either barium, sodium, 

 strontium, or ammonium ions, and furthermore that calcium is effective 

 in counteracting the toxicity of these ions. 



conclusions 



The chief conclusions to be derived from these experiments are as 

 follows : 



1. Each of the following (in the order given) is poisonous to seedlings; 

 Ba, Sr, NH3, Mg, Na, K. 



