106 HOW CROPS GROW. 
meant simply an albuminoid, or mixture of albuminoids, 
but the organized granules found in the plant, of which 
the albuminoids are chief ingredients. 
In Fig. 18 is represented a magnified slice through the 
outer cells, (bran,) of a husked oat kernel. The cavities 
of these outer cells, a, ¢, are chiefly occupied with very 
fine grains of aleurone, (casein.) In one cell, b, are seen 
the much larger starch grains. In the interior of the oat 
kernel and other cereal seeds, the cells are chiefly occupied 
with starch, but throughout grains of aleurone are more 
or less intermingled. 
Fig. 19 exhibits a section of the exterior part of a flax- 
seed, The outer cells, a, contain vegetable mucilage; the 
interior cells, e¢, are mostly filled with minute grains of 
aleurone, among which droplets of oil, 7, are distributed. 
In Fig. 20 are ee 
shown some of the 
forms assumed by in- 
dividual albuminoid- 4 b i d é 
grains ; @ is aleurone Fig. 20, 
from the seed of the vetch, 6 from the castor bean, ¢ 
from flax-seed, d from the fruit of the bayberry, (Myrica 
