1910] SCHREINER & SKINNER—ORGANIC SOIL CONSTITUENT 179 
trace out this matter, a comparison of the three experiments has 
been made and is hereby presented. In this way the solutions 
which contained in all cases 50 per cent or more P,O, are considered 
in one group; all those which contained 50 per cent or more NH, 
in a second group; and those with 50 per cent or more K,O in 
a third group. By grouping the cultures thus, an average result 
is obtained with the mainly phosphatic, mainly nitrogenous, and 
mainly potassic fertilizers. 
A comparison of the average green weight in each of these 
groups of cultures was made with those in the corresponding 
groups in the cultures where dihydroxystearic acid was absent. 
The relative growths thus obtained, taking the growth without 
the wena on acid as 100, are contained in table I. 
TABLE I 
SHOWING THE AVERAGE RELATIVE GROWTH MADE IN THE GROUP OF SOLUTIONS WITH 
DIHYDROXYSTEARIC ACID AND CONTAINING FERTILIZER SALTS HAVING THE COM- 
POSITION OF 50 TO loo PER CENT OF ANY ONE OF THE COMPONENTS P.O;, NH,, 
AND K,O. 
RELATIVE GREEN WEIGHT. 2. ; 
(Green weight wit Too) 
EXPERIMENT | 
P.O; NH; : 
50-Ioo per cent _ §9-100 per cent ee 
Reve prih oye eae 49 67 43 
Mieco 60 62 62 
Be ee 71 68 = 
In the first column is given the number of the experiment; in 
the second column the average relative green weight obtained in 
the solutions having mainly phosphatic fertilizers; in the third 
column the same result for the cultures of mainly nitrogenous 
fertilizers; and in the fourth column the results obtained when 
mainly potassic fertilizers were present. The results indicate, as 
was pointed out in discussing the experiment more fully described 
in this paper, that the mainly nitrogenous fertilizers enabled the 
plants to make a more normal growth than, on the whole, do the 
other fertilizers, although with the quantities of salts and harmful 
substance used in these experiments, the plants were by no means 
weg to overcome the harmful effect entirely, if indeed this is pos- 
s 
