Antitoxic Action of Certain Bases 123 



quently declared that between other pairs of mineral nutrients no relations 

 of the same class occur. 



In studying the effects on plants of certain salts of alkalin soils, Kearney 

 and Cameron (1902) greatly extended the knowledge of toxic and antago- 

 nistic effects. Some of their conclusions are the following: 



" Calcium chloride in pure solution is ten times less injurious than 

 sodium chloride, and two hundred times less injurious than magnesium 

 sulphate, if chemically equivalent solutions are considered. 



"Addition of sodium ions to a solution containing magnesium ions in 

 most instances marked) j^ weakens the toxic action of the latter. 



"Addition of calcium ions to solutions containing either sodium or 

 magnesium ions nearly always counteracts to an extraordinary degree the 

 injurious effect of the sodium or magnesium ions, this beneficial infiuenee 

 being usually much more marked when calcium is furnished as the sulphate 

 than when the chloride is added. 



" The effect of one kind of ion in counteracting the physiological action 

 of another kind can not be entirely explained by a study of the chemistry 

 of the solution itself, but must in part be referred to complicated changes 

 in the protoplasm of the organisms. The theory that ions furnished by 

 the dissociation of electrolji:es form intimate combinations with the pro- 

 teids of protoplasm, and that their mutually antagonistic effect expresses 

 itself in a replacement of one kind of ion by another as a result of change 

 in the composition of the surrounding solution, would appear to afford the 

 key to this problem." 



The results from one of the more general studies undertaken by Oster- 

 hout (1906) may be noted in this connection. These conclusions are impor- 

 tant, although at the time Osterhout was apparently unaware of the 

 earlier work on plants. He placed several forms of marine algae in pure 

 and mixed salt solutions and determined the duration of life in days. The 

 following conclusions are drawn: 



"1. Each of the salts of the sea water is poisonous where it alone is 

 present in solution. 



"2. In a mixture of these salts (in the proper proportions) the toxic 

 effects are mutually counteracted. The mixture so formed is a physio- 

 logically balanced solution. 



"3. Such physiologically balanced solutions have the same fundamental 

 importance for plants as for animals." 



