302 BOTANICAL GAZETTE [OcTOBER 
NOTE ON BALANCED SOLUTIONS 
Some statements by Professor W. J. V. OstERHOUT in the February 
number (p. 125) of the BoranicaL GAzeETTE in reference to balanced 
solutions require correction. 
1. Balanced solutions, which are not complete culture solutions, were 
constructed and described? by me in 1892. 
2. A balanced solution, which is at the same time a complete culture 
solution, is the solution of Knop, proposed about sixty years ago. The 
“confusion” supposed by OsTERHOUT does not exist in this particular. 
3. OSTERHOUT claims to have discovered an antagonistic action of 
potassium to magnesium. But I observed long ago that secondary potas- 
sium phosphate can retard the poisonous action of magnesium sulfate;* 
and also that another potassium salt—the monopotassium phosphate— 
accelerates the poisonous action of magnesium sulfate. 
4. OSTERHOUT claims to have discovered a poisonous action of pote: 
sium salts. But I have observed Spirogyra alive for three weeks m @ 
0.3 per cent. solution of KCl?, and alive for ten weeks in a 0.1 per oe 
solution. In a 0.3 percent. solution of K,SO,, the alga cells remained alive 
for over four weeks. The definition of OsteRHouT, therefore, must be 
restricted to certain conditions. I have deprived young barley plants 9 
endosperm, and kept them alive in 300° of a 0.5 per cent. solution of 
K,SO, for over two months. Is it possible that here the small amount of 
magnesia in the plants has counteracted the “poisonous” action of the 
large amount of potassium salt ? : 
5. A pupil of OsterHouT claimed recently to have discovered a polson- 
ous action of calcium salts. This is not in accordance with my observa- 
tion that Spirogyra can remain alive for over sixty days in a I as = 
solution of KCl. “Poisonous,” however, is a relative and elastic set 
The favorable effect of lime upon the development of root hairs, mention 
by that author, I observed long ago.3 
6. I cannot agree with the opinion that the antagonistic 
potassium to magnesium has the same cause as that of calcium to 
sium. I suggested an explanation of the poisonous action of eure 
sulfate, and also of the antagonistic action of calcium salts, in 1892. 
* Flora 75: 382. 1892. ; Bull. Coll. 
? Loew, O., anp Aso, K., On physiologically balanced solutions. é 
Agric. Tokyo 7:no. 3. 1907. 
3 Flora 75:384. 1892; Bull. Bureau Pl. Industry, no. 45, PP- 5% 5? ion 
relation of 
magne- 
explanation 
+ Flora 75:376, 383. 1892; Bull. Bureau Pl. Industry, no. 45- My without 
? , . - * t 
has been adopted by one author, from somewhat similar observations, bu 
giving credit. 
