818 Stoward.—Amyloclastic Secretory Capacities of the 
Hansteen and Puriewitsch ( 1 . c.) contend that the aleurone layer does 
not constitute a differentiated glandular tissue, and that the secretory 
capacity of the aleurone layer cells is not, unit for unit, superior to that 
possessed by those of the subjacent amyliferous tissue. 
In other words, they regard the aleurone layer as forming an undiffer¬ 
entiated portion of the reserve storage system of the seed. 
Re-investigation of the work of Brown and Morris by Brown and 
Escombe led the latter authors to consider that the aleurone layer of barley 
represents a secretory tissue. 
The assertion that the aleurone layer consists of units which are dis¬ 
tinctly living receives general acceptance. In the barley grain it consists of 
a triple layer of cubical cells with highly cuticularized cell-walls (probably 
the thickest and most resistant in the entire seed) which form an almost 
complete envelope to the inner endosperm. 
Each cell possesses a conspicuous nucleus, centrally disposed, and 
a cytoplasmic network which, prior to the inauguration of the germinative 
process, is densely crowded with, for the most part, large and conspicuous 
protein grains—the so-called aleurone grains. 
Cytological investigation shows that the aleurone layer cells closely 
parallel the columnar epithelial cells in many important respects. Fixed, 
embedded, stained microtomed material from seeds in various stages of 
germination presents features which bear close similarity to those described 
for the columnar cells of the scutellum. 
In particular, the nuclear and cytoplasmic changes and those under¬ 
gone by the granular contents of the cytoplasm not only closely resemble 
but synchronize with these same general phenomena in the epithelial cells. 
Were judgement by analogy strictly permissible, the deduction might 
at once be made that, although morphologically distinct, these cells are 
similar in function to those of the columnar epithelium. 
It is noteworthy that hitherto experiments destined to demonstrate the 
possible possession of amylolytic secretory powers by the isolated aleurone 
layer have been entirely qualitative. 
Investigation of the enzymatic secretory capacity of a given tissue 
which confines itself to the determination of the capacity which that tissue 
(such as the aleurone layer) may possess of augmenting its enzyme content 
intracellularly is necessarily incomplete because it takes no account of the 
quantity of enzyme excreted, and is therefore inadequate as a criterion 
of its total secretory powers. 
Throughout this inquiry the treatment of the subject has been as far as 
possible distinctly quantitative, and the apparent non-recognition of the 
desirability of quantitative investigation has led to misapprehension regard¬ 
ing (i) the secretion of amylase, (2) its sources of origin in the germinating 
seed, and (3) the general trend of endospermic depletion. 
