BRIEFER ARTICLES 



THE NATURE OF BALANCED SOLUTIONS 



In his recent "Note on balanced solutions" 1 Professor Loew criticizes 

 some of my statements. The following reply is inspired solely by the 

 desire to obviate if possible any misunderstanding regarding the nature of 

 a balanced solution. 



A balanced solution is defined by Loeb as one in which the toxic 

 effects which each salt would have, were it alone present in solution, are 

 inhibited by one or more antagonistic salts in the solution. 



Professor Loew objects to the term toxic as applied to calcium and 

 potassium salts. His statement that I and a pupil claim to have dis- 

 covered the poisonous action of potassium and calcium respectively is 

 evidently due to a misapprehension. On the contrary, we treated them as 



in question. 



surprise 



determined 



with 



with those of p 



solution of an indifferent substance, if such can be found. In the absence 

 of the facts needful for such a comparison, it is not possible to say whether 

 the effects observed by him are to be regarded as toxic or not. At the 

 concentration chiefly used in my experiments ( . 1 2 M) roots of wheat 

 reached a length in KC1 of 63™™, in CaCl a of 84™™, in an isotonic balanced 

 solution of 360*™, and in distilled water of 740™° I may add that for 

 certain forms of Vaucheria KC1 and CaCl 3 at the dilution of . 001 M (or 

 even less) may be toxic, inasmuch as they kill the algae in three or four 

 days, while in distilled water or dilute sea water of a hundred times greater 

 osmotic pressure, they remain alive for many weeks. For such forms the 

 components of Knop's solution including the K and Ca, taken individually, 

 would prove poisonous. But for such plants as wheat the concentration 

 of Ca and K used in Knop's solution is too weak to be regarded as toxic 

 Professor Loew's designation of Knop's as a balanced solution seems, 

 to say the least, very misleading. In a balanced solution the components 

 are poisonous when taken separately. But Professor Loew tells us that 

 neither calcium nor potassium salts are to be regarded as poisonous. 

 They are important constituents of Knop's solution. How then does he 

 regard it as a balanced solution ? Only it would seem (since here the 



Gazette 



Botanical Gazette, vol. 47 ] 



1 



48 







