MORPHOLOGY OF THE BARLEY GRAIN. 25 
fig. 6.) Given the same area in contact with the endosperm, the 
epithelial layer composed of long cells will have a much greater cubical 
content. Also, if the cells be narrower, their total number will be 
greater in a given area. If Torrey’s conclusion that the nucleus is 
the final organ to which secretion is due is correct, this increase in the 
number of cells and in the consequent number of nuclei is an actual 
increase in secreting power. In any ease, it is reasonable to assume 
that a greater number of cells with a greater plasmic content is more 
efficient than a smaller number of celis with a smaller plasmic content. 
The existence of this type 
of epithelial layer in the 
most prized malting bar- 
leys gives corroboration to 
this belief. The long, nar- 
row cell prevails in the bet- 
ter sorts, but becomes less 
prominent as the quality 
decreases. 
An ideal grain of barley, 
then, is one possessing a 
relatively short longitudi- 
nal and a correspondingly 
long transverse diameter, 
with both the distal and 
proximal ends broadly oval. 
It contains an embryo with 
a large scutellum reaching 
over the edges of the endo- 
sperm and an_ epithelial 
layer composed of long, 
narrow cells. 
An inferior grainof barley 
Fig. 6.—T wo types of epitheliai layers: A, An inferior epithelial 
layer of short, broad cells; B, an eilicient epithelial layer of 
is elongated and is pointed long, narrow cells. (Camera lucida drawings of actual 
¢ specimens. ) 
at both ends. It contains 
an embryo with a narrow scutellum the epithelial layer of which is 
made up of short, broad cells. 
A barley having the most perfect construction for the production of 
enzyms may still fall short of its highest efficiency. The size and the 
quality of the secreting surface are the structural factors of potential 
energy, but they are limited by a third element, namely, condition. 
If they are not in the highest state of vital energy, their maximum 
efficiency will not be realized; and, furthermore, this vital energy 
must be in a certain state of activity not entirely understood and 
difficult to define, which may be designated, for want of a better 
term, as ‘‘potency.’’ For example, at the time of the maturity of the 
