404 Collins .— The Structure of the Integumentary System of the 
In the embryo, the furrow side became coloured yellow. It is pre¬ 
sumed that iodine passed to it from a point at the germiual end of the 
furrow. The yellow coloration spread round the rim of the scutellum ; 
the radicle with the root-cap and sheath became browned very early, 
probably by reason of the entry of iodine from the micropyle, while the 
plumule with its sheath, although apparently turgid, and the scutellum, 
with the exception of the rim, were the last to be coloured. Whilst it is 
presumed that the entry of iodine took place at two points, it is equally 
evident that the progress of coloration can also be explained on the 
assumption of its entry at the micropyle alone with subsequent peripheral 
distribution in the distal direction. 
The result of this series of experiments is to show that the entry of 
iodine solution into the barley grain is not general and uniform over the 
whole surface of the grain, but that its uptake is localized at the germinal 
end, and that it is distributed peripherally in the endosperm along the sub- 
aleuronic layer of starch cells of the curved surface. 
(b) Uptake and distribution of some acids. 
When grains were steeped in aqueous solutions of acids it was found 
that the rate at which the different acids were able to penetrate the grain 
varied considerably. The entry of sulphuric acid was so slow that 
a marked concentration of the solution took place; with acetic acid and 
nitric acid a iveakening of the strength of the solution occurred, owing to 
the more rapid penetration of the acid. The concentration effect with 
sulphuric acid was only temporary, and passed away as the grain reached 
its maximum increase in weight. 
The following experiment, with barley of the current year, is repre¬ 
sentative of a number made with grain immersed in a solution of sulphuric 
acid. 150 grm. of grain were steeped in 250 c.c. of 4-9 per cent. H 2 S0 4 , 
and maintained at 2© 0 C. approximately. 1 c.c. of the acid neutralized 
7-5 c.c. of a solution of KOH. The titre of acid in contact with barley is 
given in the third line. At the same time the percentage weight increase 
of barley soaked in a sulphuric acid solution of similar strength was taken. 
Ao. of rr.- 
ry / Time. 
Exper. 
f Acid 
Control 
Hrs.-> 
0 
7*5 
12 
7-48 
24 
7*5 
3 <> 
48 
72 
7 ‘ 5 2 
96 
Days-> 
9 16 28 
35 49 
c Acid with 
0 Barley 
>> 
OO 
8.26 
8,36 
8.4 
8.4 
8-34 
8.04 7.6 7.3 
Increase of titre 
+ 
0.34 
0*76 
0.86 
0.9 
0.88 
0.84 
0.54 0.1 ~ o-2 
% increase weight of 
barley steeped in 
h 2 so 4 
0 
31*5 
38.0 
59 *° 
62-0 65.0 
% increase when 
steeped in water 
6i-o 
65-5 
