1164 Stoward.—A myloclastic Secretory Capacities of the 
with the addition of cane sugar (5 grms. per 100 c.c. of medium), were con¬ 
tinued for thirty-three days ; the objects were then dissected into scutella, 
rootlets, and plumules, and the dissected material (after desiccation) and 
media were then investigated separately. 
TABLE XXIX. 
Culture of Embryos on Gelatine Medium with and without 
Cane Sugar. 
. 
Amylase per 20 objects per hour in 
Exp. Culture medium. medium , scutella , rootlets and plumules 
(equivalent to mg. Cu). 
1. Gelatine-M.S. + 5 % cane sugar 3-0 000 30 
2. Gelatine-M.S. alone (control) 4-0 37-0 11 
Throughout this long period of culture the embryos in Experiment 1 
apparently did not secrete any amylase; practically none was found in 
either scutella or medium. The comparatively small amounts found in the 
control (Experiment 2) are no doubt due to partial destruction of amylase 
in the culture medium, owing to the unsuitable conditions which the medium 
offers for its conservation. External factors, atmospheric oxygen and light 
(although in all these experiments the cultures were shielded from the light 
as far as possible), also probably conspire to enfeeble and destroy the 
secreted enzyme 
The embryo derives little or no nutriment from the gelatine. Through¬ 
out the many series of experiments in which gelatine media have been 
employed, no single instance of liquefaction by either the embryo or 
aleurone layer has been observed. The seedling under these conditions, in 
the absence of both available carbon and nitrogen, simply drains the 
scutellum of the valuable reserves stored initially in its tissues, reserves 
which we have assumed also serve in part for the manufacture of enzymes. 
The experiment is intended to demonstrate that when an ample supply of 
cane sugar is placed at the disposal of the embryo, it regulates and restricts 
its secretory activity even, as in the above case, when the culture period is 
markedly prolonged. 
The results comprised in Tables XXX and XXXI refer to contem¬ 
poraneous cultural experiments with embryos on the asparagin-mineral 
salt medium with and without dextrose. 
