Embryo and Aleurone Layer of Hordeum. 1183 
In ungerminated barley they assume that there exists a certain but 
variable quantity of amylase, which probably exists both in an insoluble 
and c latent 5 condition. The notable augmentation of amylolytic activity 
(or more probably of amylolytic enzyme) which follows on predigestion, 
notably with active papain, they consider is due to the liberation and 
solubilization of this ‘ latent’ enzyme, L e. enzyme, it may be, occluded by 
or associated with a protein complex, which, especially in the presence of 
active papain, by virtue of its proteolytic function, is hydrolysed, and thus 
the enzyme assumed to be in the e latent ’ condition undergoes liberation. 
Since passive papain leads to an augmentation of enzyme, and further, 
since the solution of this body possesses amphoteric properties, its functions 
are regarded as threefold; it (1) proteolyses and (2) solubilizes the latent 
enzyme, and on liberation and solubilization (3) protects it by ensuring the 
neutrality of the reaction medium. Aqueous predigestion, and particularly 
predigestion with aqueous solutions of certain neutral salts, also leads to 
augmentation of the enzyme, apparently in the main by enhancing its 
solubility. 
Whatever may be the actual condition in which the great mass of the 
amylase of the resting grain exists, and the real nature of the mechanism 
operative in its release which ultimately leads to results similar to those 
described by Ford and Guthrie, there can be little doubt that when the 
amylolytic capacity of the ungerminated barley substance is investigated 
under conditions which closely parallel those employed by these authors, 
there ensues as a final result a very marked increase in the amount of 
amylase in the material as compared with that furnished by the ordinary 
method of determination. This notable increase in the amylase of the 
resting grain has naturally redirected attention to the subject of the causa¬ 
tion of endospermic depletion. The questions which present themselves 
are, does not the residual amylase undergo similar augmentation during the 
progress of the germinative process, and does it not play a more important 
role in starch digestion than that attributed to it by Brown and Morris ? 
Prima facie considerations would naturally suggest that it does or may do 
so, but experimental evidence, at least for the time being, does not wholly 
support this hypothesis. 
The pre-existent amylase of the resting grain was regarded, prior to 
the investigations of Ford and Guthrie, and justifiably so, as a small fraction 
only of that found in the inner endosperm of the seed after three to four 
days under conditions favourable to germination. 
(Journ. Soc. Chem. Ind., 1904, xxiii, p. 414; and Joum. Chem. Soc., 1906, lxxxix, p. 76); 
they consider that the increases of activity observed are not due to specific augmentation of the 
activity of the enzyme. 
In short, the general conclusion to be gathered from their contribution is that the results 
recorded are due to the actual increase of amylolytic enzyme. 
4 H 2 
