Dennision—The Structure of the Starch Gram. 531 
by allowing a dilute solution of gentian violet to run under the 
cover. The layers inside this outer layer begin to absorb the 
stain at once but the outer layer is not at all affected. The 
violet stain passes through the outer layer without being ab¬ 
sorbed. Of the layers inside, some are stained a deep violet, 
others take up only a small amount of stain and appear pale 
violet in color. 
Starch grains artificially corroded by diastase were also 
studied to learn if possible which part of the grain, the violet 
or the orange layers', would be affected more readily. 
In starch grains which have been treated with diastase for a 
number of days, characteristic corrosion figures appear. Large 
eccentric Ganna grains corroded in this manner show the outer 
orange layer still intact except for one or two small areas usu¬ 
ally at the posterior end. The outer violet layers have been 
dissolved in a number of places, but remain, fairly intact. Con¬ 
siderable substance has been removed from the interior of the 
grain, and other parts remaining in the center are stained 
orange. 
In, some cases the center of the grain has been, completely dis¬ 
solved and there is only a shell remaining made up of parts of 
the outer violet; layers. 
In the case of barley grains when corroded in this manner, 
the solution takes place in interrupted concentric circles, cer¬ 
tain layers appear to be more easily dissolved by the diastase 
than others. Here, also, the center of the' grain seems to be 
most susceptible to diastase action. Ho orange material is 
present outside the violet layers in these corroded grains, but 
the parts remaining in the center take the orange stain. 
It is noticeable that in a corroded grain, the portions of the 
layers bordering upon corrosion channels show a, margin of 
orange stained material, which blends gradually into the violet 
of the unaffected portions. 
In many cases in starch grains the outer orange layer is 
divided into; a number of separate layers. These are rarely 
uniform either in extent or staining qualities. The inner lay¬ 
ers grow thinner as they pass towards and around the hilum. 
Where there are several orange staining layers, the inner ones 
invariably show a. trace of violet, although predominantly 
orange in color. This would seem to indicate that the orange 
staining material surrounding the grain passes gradually and 
