1910] SCHREINER & SKINNER—ORGANIC SOIL CONSTITUENT 171 
Lower concentrations of dihydroxystearic acid would doubtless 
be better suited for a more thorough study of this matter. 
Some of the plants grown in solutions with and without dihy- 
droxystearic acid are shown in figs. 3, 4, and 5. - The cultures taken 
represent a fertilizer rich in phosphoric acid, one rich in nitrate, 
and one rich in potash. The results shown in these photographs 
are representative of the general effect over all the region of the 
triangle from which they are taken. 
GREEN WEIGHT OBTAINED IN THE VARIOUS CULTURES 
The green weights obtained in the 66 cultures of the first set 
are given in the triangular diagram shown in fig. 6. It will be seen 
that, in harmony with the results given in the previous paper report- 
ing the experiment without the harmful substance, the growth 
with the single elements or along the lines where mixtures of two 
occurred was in general less than within the triangle. The region 
of greatest growth in the solutions without the dihydroxystearic 
acid was approximately in the middle of the 10 and 20 per cent 
phosphate lines. In the dihydroxystearic acid cultures it might 
be said in general that this region of greater growth was displaced 
along these lines toward the nitrogen side. 
The total growth made in the 66 cultures without the dihydroxy- 
stearic acid was 207 grams as against 114 grams in, the case of the 
66 cultures with the 50 parts per million of dihydroxystearic acid, 
or, putting the first as too, the latter becomes 55. In other words, 
the plants with the dihydroxystearic acid made only, as an average 
of the 66 cultures, a growth of 55 per cent. It will be seen that the 
harmful substance produced its greatest effect in general along the 
periphery of the triangle, except, perhaps, along the phosphate- 
nitrogen line. In the interior of the triangle, where the greater 
growth occurred under the more normal conditions, the depression 
caused by the substance was not so marked, and this seems to be 
especially true in the region nearer to the nitrate end, in which, as 
already pointed out, the greater growth occurred in the cultures 
where the dihydrasystearic acid was present. 
