H53 
Embryo and Aleurone Layer of Hordeum . 
In view of this evidence it is difficult to avoid the conclusion that it is 
the amylase secreted by the aleurone layer , and this enzyme alone , which in 
experiments with endosperms produces corrosion of the mature starch grains 
stored in the amyliferous cells. 
The suggestion which has been made that other substances or bodies 
derived from the aleurone layer, not of an enzymatic nature, are capable of 
transforming the amylase resident in and augmented by the inner endosperm 
into an enzyme endowed with the attributes and properties of the £ secretion * 
amylase elaborated by the living scutellar epithelium and aleurone layer, 
can hardly be regarded with favour ; for under the conditions of experiment 
described above, death of the aleurone layer does not preclude the free 
diffusion of such substances as those suggested into the subjacent amyliferous 
tissue, and if these were capable of effecting any such transformation as that 
suggested, we should expect to find as one of the first indications some 
evidence of starch-erosion. Since this is not the case, there remains only 
to reiterate the statement, that it is the amylase secreted by the aleurone 
layer which produces the phenomenon observed, and dominates endospermic 
depletion (as exhibited by the isolated endosperm), and to repeat that the 
processes which occur in the isolated inner endosperm are distinctly and for 
the most part of an auto-digestive nature, such as those which a dead 
enzyme-containing tissue may be capable of inducing in its contents. 
II. Cultures of endosperms and inner endosperms on moist calcium 
sulphate. 
Similarly constituted experiments were carried out with endosperms 
and inner endosperms on moist calcium sulphate, the antiseptic now being 
nitrobenzene, and the temperature of these ‘ culture ’ experiments being 
24° C. 
The results are shown in Table XXIV below, and the conclusions to be 
derived from them are in no way opposed to those furnished by the gelatine 
cultures. 
There is an entire absence of eroded starch grains in Experiment 3 
(a phenomenon which is invariably in evidence when the aleurone-layer 
functions are not interfered with), and the total reducing sugars found in 
the medium and objects belong to the same order of magnitude as in 
Experiments 1 and 2. 
