164 BOTANICAL GAZETTE [SEPTEMBER 
Dihydroxystearic acid can also be prepared in the laboratory 
by starting with oleic acid, which by treatment with nitrous oxid 
is changed to the isomeric elaidic acid. The elaidic acid thus 
formed is dissolved in a solution of potassium hydroxid and 
oxidized by a solution of potassium permanganate, one of the 
products under suitable conditions being dihydroxystearic acid. 
G. 1.—Wheat seedlings grown in extract obtained in the method for isolating 
Fi 
< : : é 2 ct 
dihydroxystearic acid from soils: I, 2, undiluted extract; 3, 4, one part of extract, 
one part of distilled water; 5, 6, one part of extract, nine parts of distilled water. 
Care has to be taken that the oxidation does. not proceed too far, 
for the dihydroxystearic acid, as already mentioned above, is very 
readily oxidized to other compounds. | 
In this paper are reported experiments on the effect of a hee 
soil constituent upon plant growth and upon soil solutions an 
fertilizer action, especially with reference to the ratio of phosphat® 
nitrate, and potash originally present and removed by wheat a 
lings in the course of the experiment. 
