396 Collins.—The Slructnre of the Integumentary System of the 
of liquids within the grain is considered it will be shown that distribution 
is always from the germinal towards the apical end. 
(c) Degree of permeability of the cuticularized integument to water . 
Many endeavours were made to make use of a portion of the coverings 
of the grain as a septum in an osmotic cell, in order to study the degree to 
which the cuticularized membranes were 
permeable to water. One attempt proved 
successful. 
For this purpose grains were soaked for 
a short time in water, dried superficially, 
and halved longitudinally in a plane at right 
angles to the furrow. The half with the 
convex external surface was then flattened 
somewhat by gentle pressure and a circular 
portion cut out by means of a sharp cork- 
borer. This thick circular plate was painted 
very carefully round the edge with rubber 
solution and pushed into a slightly tapering 
tube by a glass rod. By this means the 
circular piece of grain-covering, with some 
amount of the endosperm attached, was 
caused to make good contact with the walls 
of the glass tube. To obtain an osmotic 
suck, the tube was filled with a 20 per cent, 
solution of salt. The lower end was im¬ 
mersed in distilled water in an open beaker, 
whilst the upper flanged end was prolonged 
by a tube of narrow bore carried in a rubber 
cork. (See Fig. 5.) Air within the tubular 
portion below the membrane was removed. 
Starch and aleurone cells were on the upper 
side of the membrane exposed to the salt 
solution. 
The apparatus was set up on June 13, 
1914. Five days elapsed before any rise was 
noticed in the level of the salt solution 
within the tube. After this the rising con¬ 
tinued very slowly. # On the eleventh day the 
external water was tested for salt, but none was found. After thirty-five 
days the level had risen 4-2 cm. in a tube of 2*5 rnm. bore, and, as traces 
of salt were found in the distilled water outside, the tube was placed in 
a saturated solution of chloroform water contained in a conical flask whose 
