the Protein Bodies of Zea, Ricinus , and Conopholis. 351 
in size, the diameter of the larger* equalling one-third that of the nucleus. 
They are very numerous, and, unless the sections are very thin, they give 
the cells a dense black colour. In a section of an entire grain of corn at this 
stage of development, the aleurone layer stands out in striking contrast 
with the rest of the endosperm, although the cells which make up the bulk 
of the rest of the endosperm are rich in small, globular protein granules 
which behave towards stains precisely like those in the outermost, or 
aleurone layer (Fig. 4). Fig. 3 was drawn from the very thin section. As 
will be seen from this figure the aleurone granules vary in size, and among 
them are to be observed many very small granules. It is inferred that the 
larger granules have developed from the smaller. I was not able to 
convince myself that the very small granules fuse at this stage to make 
the larger granules. Fusion of the granules may possibly occur at a 
later stage. 
As stated in the foregoing, the protein granules are not confined 
exclusively to the so-called aleurone layer. Fig. 4 represents three cells 
immediately below Fig. 3, less highly magnified. The protein granules are 
much smaller, more uniform in size, and very numerous. They are about as 
large as the aleurone granules in the aleurone layer at the stage of Fig. 2. 
In the first layer of cells beneath the aleurone layer usually no starch 
is present, although an occasional grain is not unlikely ; in the second layer 
of cells a few starch grains are present, while in the third layer, in which 
the cells have greatly increased in size, much starch is present (Fig. 4). 
Figs. 3 and 4 were taken from Golden Bantam sweet corn. In this variety 
compound starch grains predominate, while in starchy corn the . simple 
starch grains prevail (Fig. 5). The writer is not prepared to say whether 
this statement is true for all sweet and starchy corn respectively. As we 
go deeper in the endosperm the globular granules seem to become less 
numerous, while the starch increases in quantity. In Golden Bantam sweet 
corn the more deeply lying endosperm cells contain much more starch than 
in the lower cell of Fig. 4, and they are larger. Many of the starch grains, 
' as stated before, are compound, varying greatly in size, and composed of 
from two to several smaller grains. Among these lie numerous smaller, 
simple grains. Many of these are just large enough to show a starch 
inclusion. It is possible, therefore, that some of the smaller granules in 
the lower cell of Fig. 4 are the primordia of leucoplasts. 
When the grain of corn is only a little more mature than the stage 
from which Figs. 3 and 4 were taken, the aleurone layer and the remaining 
endosperm become so hard on dehydration that the preparation of thin 
sections from embedded material is almost impossible. The writer was 
not so much interested in the further behaviour of these bodies during the 
final steps in the maturing of the grain of corn as in the origin of the bodies 
in question. 
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