814 Stoward.—Amyloclastic Secretory Capacities of the 
An obvious increase in the amount of enzyme secreted with prolonga¬ 
tion of the culture periods is evident, and the optimal output of amylase 
evidently does not coincide with the higher concentrations of asparagin, 
but lies between the limits comprised in the 0-55 and 0-055 concentrations, 
if not beyond this latter. 
When asparagin only is used, as shown by the results of Experiment 3, 
the secretory activity of the embryo falls enormously, and in comparison 
with Experiments 1 and 2 the result points to the probable influence 
exercised by the mineral salts or by certain of them under the particular 
conditions selected. 
The results of experiments with embryos on mineral salt medium with 
and without asparagin, comprised in the following table, lend support to 
this suggestion. 
TABLE II. 
Contemporaneous Cultures of Embryos on Mineral Salt 
Medium, with and without Asparagin. 
Composition of Duration of Digestion 
culture medium. culture. period. 
Experiment 1. Seeds 48 hours 10 % copper sulphate. 
o-55 % asparagin- 
mineral salts. 4 days 2 j hours 
Mineral salts only. „ ,, 
Experiment 2. Seeds 48 hours 10 % copper sulphate. 
5 % gelatine, 0.55 % 
asparagin-mineral salts 7 days 2§ hours 
5 % gelatine, 
mineral salts only. ,, „ 
Amylase per 20 
embryos in medium , 
equivalent to mg. 
of Cu. 
61 *7 mg. 
i6«o 
T 72-7 mg. 
IT 4*7 
These experimental results indicate that the mixture of asparagin and 
mineral salts influences the secretory function more favourably than either 
alone. 
This influence is, however, only apparently shown in Experiment 1. 
In order to prevent misapprehension it must be stated that the gelatine 
medium employed in Experiment 2, by affording mechanical support to 
the plantlets, eliminates a disturbing effect which is liable to ensue in 
Experiment 1, namely, partial submersion of the embryo, which at 
once interferes with the exercise of its normal functional activities as 
a whole. 
The general conclusion, therefore, to be derived from these experiments 
is that the secretion of amylase by the embryo is principally influenced in 
some way by the presence of mineral salts, and that that induced by the 
inclusion of asparagin in the culture substratum is adjunctive. 
