Denniskon—The Structure of the Starch Grain. 529 
In 5/10 the staining, is essentially as in the latter ease with 
the exception that here we often get the orange layer divided 
by a dark line. This line, in some cases, extends entirely 
around the grain, in others it is seen on the posterior end and 
part way down the sides. 
In 5/20 the violet has been removed to greater extent in some 
of the layers in the body of the grain than in others. Certain 
broad bands seem to be not at all affected by the orange 1 . In 
some grains, two dark blue layers exist as separate broad bands 
in the body of the grain; these apparently run out into the 
orange layer where they continue as separate dark lines around 
the hilum. 
5/60 and 5/100 show no changes which can be referred to 
a longer exposure to orange. T'he layers of the inside of the 
grain are stained a pale blue in these preparations. Those im¬ 
mediately surrounding the hilum are white’. 
In 5/180 it was found that only a few layers still hold any 
violet stains. These are situated midway between the hilum 
and the posterior end of the: grain. 
It is seen by this series of slides that we may stain the whole 
grain orange in some cases where the time, of exposure to this 
stain has been of sufficient duration, but that by applying the 
stains, each for an approximately equal length of time, we get 
but a single layer of orange and that surrounding the violet 
portions of the grain. The difference in appearance of the two 
portions of the grain, the, dark violet stained body and the sur¬ 
rounding orange layer, is so striking and clearly marked that 
it seems improbable that it is due simply to* lack of penetration 
of the orange. When once the grain is stained violet, a long 
exposure to orange is necessary to remove the violet from any 
of the grain but the layer in question, while but a few minutes 
suffice to remove all traces of violet from this layer and replace 
it by orange. A short: exposure to the violet stain will often 
leave this outer layer perfectly colorless, while the inner parts 
are stained deep violet. These differences in staining proper¬ 
ties would seem to indicate that certain differences either of a 
chemical or physical nature! exist between the body of the starch 
grain and the outer layer. 
A single section from the rhizome of Ganna will often show 
all the stages in growth of the starch grains. Frequently the 
34 
