254 
K. MIYAKE. 
From the results, they concluded that the different species of plants 
differ vastly in the absolute degree of their resistance to the toxic action 
of these pure solutions, also the order of toxicity of the several salts varies 
considerably according to the species. Furthermore, the salts of magnesium 
are generally more toxic than those of sodium to all the plants tested with 
the single exception of maize. 
Burlingham 15 has studied the influence of magnesium sulphate upon 
the growth of seedlings of abutilon, peas and corn, and his results were 
summarized as follows : “Magnesium sulphate in solutions of greater con- 
centration than m/8192 has a toxic action on most seedlings, the degree 
of toxicity varying with the type of seedlings and with conditions. An 
m/8i92 solution is toxic to pea seedlings, slightly stimulating to abutilon, 
while it has a marked stimulating effect on corn seedlings. Maximum 
stimulation in magnesium sulphate results in solution from m/32768 to 
m/ 1 3 1072, the point again varying according to the kind of seedlings 
grown. When magnesium sulphate is used in proper dilutions there may 
be produced a total growth nearly double that in the control ; or in the 
case of abutilon seedlings, a growth of the primary root increased, but the 
lateral roots develop sooner, are more numerous, and attain a greater 
growth. Furthermore the stimulation is not limited to the root system, 
but the magnasium forces a more rapid and a greater growth of the 
hypocotyl and plumule. In the same concentration, calcium nitrate causes 
very little stimulation. In addition to the marked stimulation which 
magnesium sulphate causes when it is used in dilutions from m/16384 to 
m/524288, it increases the vitality of the seedlings. The seedlings grown 
in the magnesium sulphate outlived those in the control by two or three 
weeks, and in some cases by a greater period. 
From the foregoing results and conclusions, it is evident that mag- 
nesium sulphate, in the absence of other salts, is not neccessarily injurious in 
its effect, but on the other hand may be highly beneficial, while any in- 
hibitory action is due to the presence of a relatively large proportion of 
magnesium in solution’’. 
1). Burlingha m, — Jour. Amer. Chem. Soc., 29 PP. 1095-1112 (1907). 
