apkil.1907.] LOEW & ASO.—ON PHYSIOL. BALANCED SOLUTIONS. 81 



of the rest of the endosperm after they had reached 18 cm., 

 they can remain 2-3 months alive, if they are placed in 0.5% 

 solutions of KN0 3 , KC1 or K 2 S0 4 , a sure proof that the as- 

 sertion of the toxic action of potassium salts is unfounded ; the 

 older leaves die, but new ones develop, utilising mineral food 

 from the dying leaves. Similar experiments were made with 

 seedlings of maize, which were still alive 7 weeks after being 

 placed in a 0.5% solution of K 2 S0 4 . 



The antitoxic action of K to Mg is, furthermore, too weak 

 to play any decisive role in manuring. We recognised, e.g., the 

 law that the common cereals thrive best when the available 

 amounts of lime and magnesia are about equal. If now potas- 

 sium salts would exert any notable action in the sense men- 

 tioned, the maximum harvest would have been obtained with 

 very much less lime in those cases where the potassium salts 

 of the manure were increased. But as a matter of fact the 

 same lime factor was observed at very different amounts of 

 potassium salts in the manure. Some influence of potassium- 

 sulphate can however be recognised so long as the plants are 

 young. Six pots each holding 2 kilo of an exhausted loam soil 

 received the following general manure: 0.8 g. K 2 S0 4 ; 0.5 g. 

 Na 2 HP0 4 ; 0.8 g. NH 4 N0 3 , while the special manure consisted in : 



I No further addition. 



II 5g. KC1. 



III lOg. artificial magnesium carbonate. 



IV „ „ „ „ -rlOg.KCl. 



V „ „ „ „ +5g. K 2 S0 4 . 



VI „ „ „ „ +100g.CaC0 3 . 1} 

 Two pots, each with 5 barley plants served for each case. 



The seed was sown Oct. 30. The fresh weight of the young 



plants on March 16 yielded in average the following figure, g: 



I =9.5 I =3.5 



II =7.3 II =5.0 



III = 1.5 111 = 13.7 



D This large quantity was required on account of the great availability of the 

 magnesia in the artificial magnesium carbonate. The original soil contained §A% 

 MgO and 0.59^ CaO. 



