682 Wisconsin Academy of Sciences, Arts, and Letters. 
Starch grain represented in Plate XL , Figure 43. 
A (in water.) 
B ( in iodine. ) 
C (in alcohol.) 
D ( in gentian violet 
and orange Gr.) 
a —Highly refractive 
region. 
a ’—Layer which has 
not so fully taken on 
the nature of starch, 
hence is faintly blue 
in color, a” —A blue 
starch layer. 
This layer is now pale 
blue in color, the color 
becoming iighter from 
inside toward periph¬ 
ery. There is no 
sharp line separating 
two parts. 
The layer a’ is of dif¬ 
ferent composit’n and 
takes orange; a ” is 
starch and takes gen¬ 
tian violet like rest of 
grain. 
1— A dark line, prob¬ 
ably a crack filled 
with watery colloi¬ 
dal mass. 
This layer is broader 
and paler in color. 
In alcohol this layer 
is still broader. 
This layer is about 
the same width as in 
alcohol. It stains pale 
blue. 
6—Highly refractive 
layer. 
Contracted slightly 
and stains blue. 
Contracted a little 
more and blue partly 
removed. 
Characteristic blue 
stain with gentian 
violet. 
2 —A dark line sim- c and layers anterior 
ilar to 1. to £ have contracted, 
lleavingspace at 2 . 
Contraction goes on 
with consequent 
broadening of 2 . 
Stains pale blue, con¬ 
tains relatively small 
amount of starch. 
c —Slightly refract’e 
layer. 
In iodine this layer 
stains uniformly with 
those next to it on in¬ 
side. It is pale blue in 
color. 
The iodine is easily re¬ 
moved, leaving layer 
pale blue in color. 
This layer stains less 
deeply than a or b. 
In this grain there is an outer refractive region which has 
the appearance of a single layer when the grain is mounted in 
water. This outer region is similar to the region a in the grain 
represented in Figure 42. In both grains it consists of two 
layers which are differentiated by iodine or by gentian violet 
and orange. When iodine is washed out of this region, it is 
removed from a first and then gradually from the outer part 
of a", so that the sharp line separating the two layers disap¬ 
pears. 
The dark line 1 which separates a“ from b becomes 
broader in iodine, and is no longer dark, but swells somewhat 
and stains a pale blue. It becomes broader by the contraction of 
the layers a' and b and stains less deeply, probably because it 
contains less starch than these layers. This layer stains less 
intensely with gentian violet than a‘ and b, which bears out 
the assumption that it contains less starch. 
Layer b shows the same reactions to stains as a". The 
dark line 2 shows the same characteristics as 1. It does not 
