835 
Embryo and Aleurone Layer of Hordeum . 
of the contours of the inner endosperm tissue, erosion of starch granules, 
and evidence of marked change in the cell-walls of the amyliferous 
tissue. 
The latter objects, on the contrary, exhibit little if any evidence of 
visible change either in mass or condition. In one or two instances, how¬ 
ever, where a minute fragment of the aleurone layer was inadvertently left 
attached, the amyliferous tissue immediately underneath and on its margins 
when viewed by transmitted light was distinctly less opaque, and the frag¬ 
ment had literally sunk into the subjacent tissue as dissolution of the starch 
had progressed. 
Invariably, in the endosperm of the intact seed under normal germina¬ 
tion conditions, in the isolated endosperm under the cultural conditions 
here employed, action on the starch contents proceeds most rapidly, in 
point of time, in the tissue subjacent to the dorsal aleurone layer . The 
experiments just referred to demonstrate that the ventral portion of the 
aleurone layer is equally efficient in inducing transformation of the starch 
reserves placed at its disposal. The important and crucial point is that 
marked depletive change takes place, under the conditions selected, only in 
those halved objects which were not deprived of their aleurone layers. 
Where a minute fragment was all that remained, there was striking evidence 
of its influence in determining dissolution of the subjacent starch, an observa¬ 
tion rendered possible only by the lengthy duration of these culture 
experiments. 
The demonstration of the amylolytic capacity of the inner endosperm 
in Experiment 3, Table XVII, p. 833, was confined to the examination of 
cultures of these objects on agar alone. An additional series of experi¬ 
ments was therefore undertaken to ascertain whether the inclusion of 
mineral salts with variation of the concentration of the phosphate would 
influence the process of self-digestion exhibited by the inner endosperms. 
These experiments are summarized in the table below, and additional 
data of interest are also included, namely, direct and indirect estimations of 
the amounts of reducing sugars in both objects and medium, and the 
weights of the objects after removal from the culture medium and subse¬ 
quent desiccation for twenty-four hours at 30° C. 
Two methods of preparing the objects were adopted :— 
(1) The aleurone layers were filed off the air-dried endosperms, and 
the inner endosperms thus prepared were then steeped successively in 
absolute alcohol and water, forty-eight hours in each reagent (Experi¬ 
ments 1, 2, 3, and 4). 
(2) Endosperms were steeped as in (1), and the aleurone layer removed 
with a razor (Experiments 5 and 6 ). 
Method (1) excludes the possibility of enzyme passing by diffusion 
from the aleurone layer and embryo to the subjacent tissue during steeping. 
