424 TorRREY: CYTOLOGICAL CHANGES 
heavily loaded with nutritive matter, which consists, for the most 
part, of aleurone grains and oil globules. In corn, even at the 
beginning of germination, starch grains are commonly found in 
these cells. In barley, such grains, according to Morris and 
Brown, are not present in the scutellum until the endosperm 
shows signs of depletion. Nearly all the starch grains, wherever 
found, are cracked because of the dehydration of the resting 
period. 
II. Oricin oF DIASTASE 
1. Previous Accounts.—It will be sufficient, for our present 
purpose, to point out the following pertinent facts in regard to 
diastase, which have been established principally through the re- 
searches of Morris and Brown.* 
(a) There are two varieties of diatase.—One is an amylohydro- 
lytic enzyme occurring in buds, leaves and other regions, which acts 
on the transitory starch grains found in the cells of these tissues. 
It does not act on starch paste nor pit starch granules, but dis- 
solves them evenly. 
The other is the enzyme secreted by the columnar epithelial 
cells in the seeds of the Gramineae. This dissolves starch paste 
and corrodes starch granules. ee 
The former has been called by Morris and Brown the sy ~_ 
tase of translocation’’ and the latter the “diastase of secretion. 
(2) This diastase of secretion begins to be formed soon after 
the beginning of germination and continues until the endosperm 
is depleted. 
(c) The first evidence of the formation of the ferment 1s the 
appearance of granules in the columnar epithelial cells of the scu- 
tellum. Is; 
(2) Soon after the appearance of these granules the cells - 
of the endosperm nearest the scutellum begin to be dissolved an 
the contained starch grains show evidence of pitting. h 
(e) Concomitant with the above-mentioned phenomena stare 
grains appear in the cells of the scutellum immediately below the 
secreting epithelial cells, 
sie neni Peas 
* For a detailed description of the work that has already been done oe 
of diastase and its action on the endosperm, the reader is referred to the orig! : 
or to the chapter on Diastase in Reynold Green’s Fermentation. 
