2 9 2 
K. MIYAKE. 
The results show that in all the concentrations tried, the suitable 
ratio of the cations, calcium and magnesium or calcium and sodium had 
a favorable effect upon the growth of the plants. The plants did much 
better where calcium and magnesium or calcium and sodium were present 
in the ratio 5 : 25. 15 The more concentrated the solution the greater 
was the difference in effect between the ratio 5 : 25 and the other ratios. 
In higher concentrations than dicinormal, however, the plants did not 
grow so well as in distilled water even in the most favorable ratio. 
V. Influence of a third Salt upon the Growth 
of Rice Seedlings in a Mixture of two Salts. 
Some years ago Loeb !) and Ostwald ?> found from the study of 
marine and freshwater animals that as the toxicity of a pure solution is 
diminished by the addition of a second salt, so is the toxicity of certain 
mixtures diminished by the addition of a third or fourth salt, and by 
addition of various salts a mixture known as balanced solution (i. e., one 
which is no more injurious than distilled water) can finally be obtained. 
In view of this fact, Osterhout 15 made a number of experiments with 
the salts which are contained in sea water with marine, freshwater as 
well as land plants and^ proved that facts similar to those mentioned 
above are also observed even in plants. According to him, the order of 
1 ) Some years ago Loew advanced the theory that plants made their maximum growth- 
other conditions, of course, being favorable— when the available lime and magnesia are present 
in a certain ratio to each other, the optimum ratio for rice plants being to = 1. But, 
this ratio of lime to magnesia seems to apply only in a medium in which a sufficient amount 
of other nutritive salts is present. 
2) I. oeb, — Pflüger’s Archiv, 107 I’- 257 (1905). 
3) Ost wald, -Ibid., 106 P. 568 (1905). 
4) Osterhout- Bot. 'Gaz., 42 , p. 127 (1906); 44 , p. 25g (1907). 
