\ M-.w BASIS FOR BARLEY VALUATION \M> [MPROV] MINI. 5 
Ii i- therefore importanl to know where the ferments or enzymes 
necessary to bring about these changes are secreted. Are the} the 
producl of tin' scutellum, making it thereby not onhj an absorbing 
l)ii t a secreting organ ' < >r are thej located elsewhere? This i- one of 
the questions about which there is much diversity of opinion. Some 
investigators bold thai the necessary enzymes, diastase and cytase, 
;iii' to In' found in tin 1 cells of the starch endosperm itself, and that if. 
as is probable, the scutellum also secretes these enzymes ii is supple- 
mentary to the stored-up supph of the starch cells. Other- believe 
all or a considerable part of the supph is secreted 1>\ the cells of the 
aleuroD layer, which invests the entire starch endosperm excepl ;it 
i he end of the grain occupied by the plantlet. Certain authors hold 
that both this layer and the scutellum supph these ferments. Ii 
was such discordanl testimony on this and other point- that made 
necessary at the outsel a thorough stud) of the morphology of the 
barlej grain so a- to fix, a- far a- possible, the location- of these 
import ant fund ion-. 
These investigations have proved that the enzymes already men- 
tioned, the diastatic and cytatic starch ferments, are wholly the 
producl of t he scutellum and are secreted by its outer la) <•:■. called t he 
epithelial layer; that although a minute t race of t hem is to he found in 
the starch cell- (as in ail starch-containing tissue), it plays so slight a 
part in the normal -tarch conversion that it is practically negligible; 
that, furthermore, the aleuron layer has nothing whatever to do with 
this process. The scutellum can therefore he called the "malting 
organ" of the barley grain and it> epithelial cells the "malting 
glands." This organ, together with the size and quality of the endo- 
sperm, is therefore of the highest importance in all quegtions concern- 
ing the food value, malting value, ami germinating value of barle] . 
I>\ a comparative study of this important organ in the leading vari- 
eties of cultivated barley, it was soon discovered that it> shape 
varies u r reatl_\. At least two distinct types exist, with main inter- 
mediate forms- one ver\ broad, almost circular in outline, covering 
tlu 1 lower end and reaching well over the shoulders of the grain sei 
fig. 1); the other narrow . elongated, with nearly parallel -ide- and 
rounded or pointed tip (see fig. 2). The broad scutellum i- generally 
nearly ilat or so slightlj convex on it- inner surface that it lies in a 
shallow depression of the -larch endosperm, while the narrow scutel- 
lum is thick and tongue shaped and is sunken quite deep into the 
endosperm. Compare the depression shown on the left in figure I 
with that in figure '_': also tin' two scutellums. 
Corresponding differences, though less strongly contrasted, were 
found to exisl in the size and shape of the epithelial cell- clothing the 
inner surface of these two types y^( scutellum. The broad, shallow 
16] 
