816 S'toward.—Amyloclastic Secretory Capacities of the 
substance; the latter being effectively sterilized and the pre-existent amy¬ 
lase completely annihilated (as controlled by inoculation and digestion 
experiments respectively) by heating in a Koch 5 s steam sterilizer for two 
hours at ioo° C. 
In order to avoid gelatinization of the starch grains, the finely ground 
sterilized endospermic substance was thoroughly mixed with the cooled, 
still mobile gelatine prior to the transference of the mixture to the Petri 
culture dish. 
The results are embodied in the following table :— 
TABLE IV. 
Cultures of Embryos on 5 % Gelatine-Barley Endosperm 
Substance. 
Exp. 
1. 
2. 
Seeds (African barley) 48 hours CuS 0 4 , 48 hours water. 
Duration of ^..... , 
culture J Digestion period. 
6 days 1 hour 
8 >> >) 
Amylase per 20 objects 
in medium 
(. equivalent- to mg. of Cu. 
80.5 
96.7 
As already evidenced (Table I), the secretory capacity of the embryo 
augments as duration of culture period is extended. 
The following typical experiments afford further evidence of this 
feature:— 
TABLE V. 
Cultures of Embryos on 0.55 % Asparagin-Mineral Salt Medium. 
Seeds 48 hours 10 % CuS 0 4 , 1 day under aseptic germination conditions. 
Exp. 
Objects. 
Duration 
°f 
Ml If'Jl Yfi 
Digestion 
period. 
Amylase per 20 
objects in medium 
(equivalent to 
Relative 
augmentation of 
secretory capacity , 
1. 
40 embryos 
2 days 
2 hours 
mg. of Cu). 
11 
24 hours. 
2. 
33 
3 ,, 
1 hour 
10 
3 - 
3 3 
4 » 
-n 
69 
60 mg. 
4- 
33 
6 „ 
n 9 
25 „ 
5 - 
33 
8 „ 
33 
150 
*4 „ 
There is an obvious progressive augmentation of the secretory capacity 
of the embryo accompanying extension of the period of culture. 
From the results afforded by these experiments under the conditions 
selected, it may reasonably be assumed (in the absence of direct experi¬ 
mental investigation) that they are really the net result of two series of 
factors which are opposed to each other. On the one hand, production of 
enzyme by the embryo ; on the other, destruction or inactivation of enzyme 
by the operation of factors in and external to the medium, such as changes 
