So2 Stoward.—Amyloclastic Secretory Capacities of the 
of supply, huskiness and thick skin. Their germinative capacities were 
satisfactory and were subjected to frequent trials at intervals throughout 
the course of the inquiry. 
Aims and methods of investigation. The principal aims of the investiga¬ 
tion have been to endeavour to (i) show whence the amyloclastic enzymes 
are derived which are operative in influencing digestion of the amyliferous 
storage reserves of the inner endosperm and to (2) demonstrate in an 
approximate manner the contributory shares taken by these enzymes in 
the work of endospermic depletion. 
Three possible sources of amylolytic enzyme apparently exist, the 
scutellar epithelium, aleurone layer, and inner endosperm. 
The enzymes furnished by the two former are elaborated by cells 
which possess a secretory mechanism, and the continuance of their secretory 
activity depends upon their vitality. The amylases from both these sources 
are characterized by the possession of a marked power of attack on the 
mature starch grains of the inner endosperm under conditions which are 
approximately identical with those which obtain during the progress of 
normal germination. 
The increase of enzyme pre-existent in the inner endosperm (augmenta¬ 
tion of which occurs under certain experimental conditions to be described) 
does not with certainty depend upon the possession of an undoubted secre¬ 
tory capacity by this tissue ; on the contrary, this enzyme possesses but 
feeble powers of attack on the fully formed starch grains which form by far 
the greater bulk of the storage reserves of the mature grain. 
The augmentation of enzyme and the comparatively restricted amount 
of amylolytic change it is capable of inducing are therefore preferably 
referred to as being due to the generative or auto-digestive capacity of this 
tissue. 
At the outset the fact must be clearly emphasized that the amylase 
which originates solely in the inner endosperm is sharply differentiated 
from those which are elaborated by the scutellar tissue and aleurone layer 
by its feebler power of attacking, under comparable experimental conditions, 
the fully formed starch grains of the mature inner endosperm, and the 
adequate recognition of the differential powers of attack on the mature 
starch grain possessed by these amylolytic enzymes is, as we shall see later, 
of prime importance in any attempt to elucidate and explain the phenomenon 
of starch digestion of the endospermic starch reserves, and we shall further 
see that the mere capacity of a given tissue to augment its amylase-content 
is of subordinate importance unless this augmentation of enzyme is accom¬ 
panied by evidence of a commensurate increase in the amount of starch 
digestion. 
The interest attached to the work of Ford and Guthrie ( 1 . c.) relates to 
amylase of the resting grain and the possible role it may play in inner 
