Antitoxic Action of Certain Bases 



135 



The action of the calcium is a very clear case of antagonism. It entirely 

 overcomes the toxicity of both chlorid and sulfate of magnesium. It 

 appears that the magnesium antidotes the calcium to a slight extent. 

 This apparent antagonism, however, may be merely a benefit arising from 

 the addition of another essential element, or at least it may not be due 

 wholly to the antitoxic action of the magnesium. It is difficult to interpret 

 mutual antagonism from data that show great decrease of toxicity in one 

 direction and only slight decrease in the other. 



Five days after the seedlings had been placed in the solutions the 

 toxicity of magnesium was apparent. The roots in the culture contain- 



FiG. 2. — Antidotal relations between calcium and magnesium; distilled water as the solvent 



1. N/20 CaCl2 



2. N/20 CaCl2+N/100 MgCb 



3. N/100 CaCl2+N/100 MkC12 



4. N/1000 CaClo+N/lOO MgCk 



5. N/100 MgCb 



ing N/500 MgCl> were dead, no growth having taken place. Ten days 

 later the antagonism of calcium was clearly shown by the increased 

 growth of the seedlings in the combined solutions over those in the 

 solutions of magnesium alone, 



Loew (1899) has drawn attention to the relative abundance, usually, of 

 magnesium in the seeds of plants as contrasted with the magnesium content 

 in other plant structures. This excess in the seed may enable the seedling, 

 for a time at least, to exhibit a maximum growth in a solution containing 

 no magnesium. As a result of numerous nutrition experiments in this 

 laboratory with the pea, it has been clearly demonstrated that the demand 

 of this plant for magnesium, or the necessity of maintaining a certain pro- 



