274 Reed . — A Study of the Enzyme- secreting Cells in the 
A. Studies on Living Material. 
Twenty-four hours old. The protoplasmic body of the epidermal cells 
of the scutellum still shows the characteristics of the resting condition ; it 
does not entirely fill the cell-cavity. The cells contain a large amount of 
granular substance which is coloured yellowish-brown by iodine. The under- 
lying cells of the scutellum contain two kinds of granules — proteid and 
starch. 
Two days old. The cells of the epidermal layer are still closely packed 
with fine granules, but the larger proteid granules have disappeared from 
the underlying layers of cells. The nuclei of the epidermal cells, where 
observable, present an uneven contour. The scutellar cells in the vicinity 
of the plumule contain a small amount of starch. 
Three days old. This lot of seeds had made rapid growth ; when the 
embryos were removed for study the radicles were 1*5 to 2*5 cm. long, but 
the condition of the secreting-cells was only slightly more advanced than 
that described for the second day. The epidermal cells were full of small 
proteid granules, but the large proteid granules had disappeared from the 
first three or four layers of hypodermal cells. There was again an evident 
accumulation of starch about the plumule. 
Fotir days old. The radicles of this lot of seeds only average i cm. 
in length, but the cytological changes in the scutellum are farther advanced 
than in the last set. The epidermal cells contain proteid granules only in 
the distal 1 half or third of the cell. A few cells are entirely free from 
granular material. 
Seven days old. Cotyledons i cm. long, radicles 2 cm. long. The 
epidermal cells are nearly free from granules. In those cells where granules 
are found they are small, and occur only in the distal end of the cell. The 
scutellar cells have lost all of the large proteid granules, but still contain 
large numbers of the small granules. In favourable cases the vacuolate 
protoplasm may be seen. When the small granules of the epidermal cells 
disappear, the small granules of the scutellar cells, which in their turn have 
probably resulted from the disintegration of the large granules, also begin 
to disappear. 
The cells of the scutellum show an increasing amount of starch in 
the region of the plumule. After the application of iodine to the sections 
the consequent darkening can be seen plainly by the naked eye. The 
presence of this starch has two possible explanations — it may arise indirectly 
from the breaking down of proteid matter in the scutellum (cf. Timberlake> 
’01), or it may be formed by the anhydration of some soluble carbohydrate 
derived from the endosperm. 
1 In the subsequent descriptions of epidermal cells, the term * distal ’ refers to the end of the 
cell in contact with the endosperm, 1 proximal ’ refers to the opposite end. 
