Embryo and Aleurone Layer of Hordenm. 1185 
manner and to the same extent as when the glandular tissue exer¬ 
cises its full functional powers ? Why does not the amylase of the resting 
grain, as suggested by Ling ( 1 . c.), undergo transformation into the amy¬ 
lase of the malted grain and acquire the properties of the latter as we 
know them ? Evidence will be adduced showing that the amylase 
derived from the aleurone layer possesses marked powers of attack on 
barley starch grains, the grains undergoing distinct and visible erosion. 
On the other hand, the amylase of the inner endosperm possesses but 
feeble powers of attack on the mature starch grains, and the erosive features 
are entirely absent. As we shall see when we come to deal with the 
experiments relating to papain-digestion, which lead apparently to the 
release of considerable quantities of the amylase resident in the inner 
endosperm, the fact, important as regards endospermic depletion, is brought 
to light that here also, in spite of the amount of diastase in action, the 
digestion of barley starch placed at its disposal under the condition of 
experiment is negligible. Still other important facts, relative to the nature 
of this enzyme and the condition in which it exists in the inner endosperm, 
will be advanced when we come to consider the results of the investigation 
of the structural parts of Tropaeolum, in which presumably the amylase 
present is wholly represented by the 4 translocation ’ variety, 
It appeared desirable, therefore, in view of the importance and 
stimulative interest possessed by the valuable contribution of Ford and 
Guthrie, to investigate, along lines closely parallel to those devised by them, 
the Chilian barley which has served in the majority of the experiments 
described, and further to extend the inquiry to the investigation of 
germinated material. 
Investigation of air-dried and steeped material . 
Materials derived from air-dried and steeped seeds were first investigated 
by the ordinary direct method of digestion with soluble starch, i. e. the 
finely-ground material was directly added to the starch solution at 30° C, 
and the digestion continued at this temperature for a definite time-period, 
the object of these experiments being to ascertain whether the amylase 
content undergoes diminution after steeping, and also the influence exercised 
by the husks or certain of their constituents (organic and inorganic) on the 
result. 
The results of the first series of experiments are given in the following 
table:— 
