226 
Journal of Agricultural Research 
Vol XXVIII, No. 3 
The removal of iodin by the nearest starch layer was corroborated by experi¬ 
ments with three-eighths inch cubes of dry starch gels, placed in iodin solution. 
These became completely soft through entrance of water but remained colorless 
except for a blackened surface layer which was narrow and fairly well delimited 
in cross-section. 
Microtome sections of immature wheat seeds fixed in Flemming’s strong 
solution showed near the distal end a deep blackening of the cutin layer (more 
strongly cutinized in the mature seed) with scarcely any discoloration at the 
embryo end, and a gradation of color between. The greater degree of cutiniza- 
tion first demonstrated by osmic acid in a direction opposite to the permeability 
to iodin was subsequently found in the mature seed by the use of Flemming’s 
triple stain and this makes it certain that the cutinization gradient remains 
nearly the same in the mature seed, although this may be obscured owing to 
the higher degree of cutinization attained in the entire surface layer. This 
indicates a cvtological basis for the gradient of permeability experimentally 
observed. 
