1200 Stoward.—Amyloclastic Secretory Capacities of the 
inner endosperm, the dead nature of this tissue, and its finite enzyme- 
augmentative capacity, &c., that the ‘latent’ enzyme of the barley-endo¬ 
sperm may actually represent an enzyme undergoing step by step a series 
of complex retrograde changes, the final terms of which may be 
simply the more or less complex protein reserves of the inner endosperm. 
If such a view be correct, then the ‘ latent ’ amylase of this tissue re¬ 
presents an enzyme which has undergone partial retrogradation, i. e. a 
complex, one portion of which consists of unchanged amylase, the other 
of amylase which has undergone transformation into protein reserve sub¬ 
stances. 
The view propounded merely attempts to suggest a possible explana¬ 
tion of the results which follow on predigestion of the inner endosperm 
with papain, and to hint at the possible mode of origin of the ‘ latent ’ 
amylase of the resting grain of the inner endosperm. 
The results recorded in this section show, at least, that papain- 
digestion as a means of determining the higher limiting value of the 
amylase content of a given tissue is not of universal application. 
The results are in no way equivocal ; direct digestion in all cases yields 
results which are superior in order of magnitude to those furnished by 
papain-digestion. 
XVI. Summary of Conclusions. 
The whole of the experimental work described in this paper, com¬ 
prising an investigation of 
(i) the separate amyloclastic secretory capacities of the embryo and 
aleurone layer ; 
(a) the amylase augmentative and depletive capacities of the endo¬ 
sperm and inner-endosperm ; and 
(3) the demonstration of the possession of a cytoclastic secretory 
capacity for the embryo and aleurone layer of the seed of 
Hordeum , 
has been carried out with the sterilized objects and under rigidly aseptic 
conditions. Throughout, the aim has been to measure quantitatively the 
amyloclastic capacities of the three principal anatomical parts of the seed 
(embryo, aleurone layer, and inner endosperm), in order to ascertain as far 
as possible the (1) sources of origin of the amylases which accumulate 
in the inner endosperm during the progress of the germinative processes, 
(2) their relative magnitudes, and (3) the shares the amylases which are 
elaborated or generated in these tissues take in the digestion of the starch 
reserves stored in the inner endosperm. 
The following conclusions appear to be justified by a general survey of 
the results furnished by this investigation :— 
1. Direct experimental investigation of the amyloclastic secretory 
