Barley Grain in Relation to Localized Water Absorption. 401 
theless in the course of a few hours two blue points, situated on either side 
of the furrow at its germinal end, indicated the penetration of the iodine 
to the starchy endosperm. Spreading quickly from these points the 
coloration proceeded distally as above described, stopping on the furrow 
side after a band of a certain breadth had been coloured. Fig. 7 represents 
the distribution of the colour change in a series of barley grains after 
Dorsal. Ventral. Dorsal. Ventral. 
Fig. 7. Distribution of iodine. Exterior view. 
increasing periods of immersion in a solution of iodine. Both curved and' 
furrowed side of each grain are shown. 
There is but little doubt that non-coloration of the starchy endosperm 
on the flanks of the furrow is due either to the peculiar configuration of 
the tissues in this region, which prevents the rapid penetration of liquids 
in this direction, or the absence of the small sub-aleuronic cells with "small 
starch grains along which the iodine quickly makes its way, or both. 
Experiments show that these cells imbibe and swell rapidly, and it is 
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