262 
K. MIYAKE. 
and bicarbonate show in concentration of 1/500-1/1000 and 1/100 nor- 
mal respectively. 
4) The toxicity on the growth of rice seedlings appears in the case 
of magnesium sulphate and chloride, calcium chloride, sodium chloride and 
carbonate in concentration greater than 1/100 normal, while sodium 
sulphate and bicarbonate each in concentration greater than 1/50 normal. 
The maximum stimulation point of these salts is attained in the dilution 
of 1/500 normal for magnesium sulphate, 1/1000-1/5000 normal for mag- 
nesium and calcium chlorides, 1/50-1/100 normal for sodium sulphate, 
1/100 normal for sodium chloride, 1/1 00— 1/500 normal for sodium car- 
bonate and bicarbonate. 
5) The toxic and highest stimulating effects of the salts upon the 
growth of rice plants in the experiment with the soil we used are shown 
in the following amounts : 
Salts 
Amount of salt added to 2000 g. of soil 
Toxic amount 
Highest stimulating amount 
g. inul wt. 
g. mol wt. 
MgS0 4 
L 
lO 
] _ 1 
20 200 
MgCl 2 
1 1 
20 100 
X — 1 
100 200 
CaCl 2 
1 
IOO 
_1 Li. 
200 lOOO 
Na 2 S0 4 
_1 1_ 
20 IOO 
_JL 3 
200 1000 
NaCl 
1 
2 0 
1 _ 1 
100 200 
Na 2 C0 3 
1 
20 
_1 L_ 
100 1000 
NaHC0 3 
1 
lO 
1 1_ 
IOO 200 
6) The amount of toxic and highest stimulation of the salts upon 
the growth of rice plants varies with the nature of the culture media. It 
is generally higher in soils than in pure solution. 
7) The resistant power of rice toward these salts seems to be almost 
equal to that of wheat and weaker than maize, but stronger than oats and 
sorghum. 
