839 
Embryo and Aleurone Layer of Hordeum . 
TABLE XX. 
Culture of Endosperms and Inner Endosperms on Moist Cal¬ 
cium Sulphate (Kahlbaum). 
Chilian barley. Culture period, 10 days. 
Total reducing sugars 
Exp. Objects. 
in medium equivalent 
to milligrams of Cu. 
1. 20 endosperms 
601 
2. 20 inner endosperms 
133 
3 - 
123 
Experiment i. Endosperms of air-dried seed steeped successively in (i) absolute alcohol; (a) 
water ; 48 hours in each reagent. 
Experiment 2. Aleurone layers filed off endosperms of air-dried seed ; inner endosperms, thus 
prepared, then steeped as in Experiment 1. 
Experiment 3. Intact seeds steeped successively in (1) absolute alcohol; (2) water; 48 hours in 
each reagent; embryos excised and aleurone layers removed with razor. 
The contrast in the results afforded by Experiment i and Experiments 
2 and 3 is most marked. In the space of io days 75 % of the endosperms in 
Experiment 1 zvere almost completely emptied of their inner endosperm con¬ 
tents ; in the remaining 25 % the contents were in a semi-solid condition, and 
gentle pressure only was necessary to cause free ejection of their contents. 
The inner endosperms (Experiments 2 and 3), on the contrary, had 
suffered little or no reduction in mass, and had the semi-solid consistency 
characteristic of similar objects which had been simply steeped and subse¬ 
quently maintained in a moist condition. 
These experimental results afford most convincing evidence, on the 
one hand, of the capacity of the endosperm, and, on the other, of the relative 
incapacity of the inner endosperm to induce complete and veritable deple¬ 
tion of the inner endosperm contents. The former result is conditioned by 
the presence of the aleurone layer, the latter by its absence. 
The relative order of magnitude of the two capacities is also well 
shown by the relative amounts of reducing sugars in the substrata given in 
the above table. 
The points of difference are still further emphasized by the contrast 
revealed by microscopical examination of starch granules from the two 
types of objects. These, in Experiment 1, exhibited extensive erosion, 
which is so closely similar to that hitherto attributed exclusively to the 
amylase secreted by the embryo (‘ amylase of secretion ’) that there is full 
justification for the statement that the enzyme secreted by the aleurone 
layer is identical with that elaborated by the embryo. 
Microscopical examination of starch grains taken from various parts of 
the inner endosperms (Experiments 2 and 3) fails to reveal either any signs 
of erosion or any visible evidence of dissolution of the larger mature starch 
granules; they retain their characteristic lenticular shape, and the opinion 
is reiterated that in all probability the attack of the amylase on the inner 
