22 ELEMENTS OF BOTANY. 
Test in this manner wheat (in the shape of flour), oats (in oatmeal), 
barley, rice, buckwheat, flax, rye, sunflower, four-o’clock, morning-glory, 
beans, peanuts, hazel-nuts, and any other seeds that you can get. | 
Report your results in tabular form as follows : 
Mucu Srarcu. LitrLe STARCH. No Srarcu. 
Color, blackish or Color, pale blue or Color, brown, orange, 
dark blue. greenish. or yellowish. 
31. Microscopical Examination of Starch. — Examine starch in water 
with a rather high power of the microscope (not less than 200 diameters). 
Pulp scraped from a potato, wheat 
flour, the finely powdered starch sold 
under the commercial name of ‘‘corn- 
starch’ for cooking, oatmeal and buck- 
wheat finely powdered in a mortar, will 
furnish five excellent examples of the 
shape and markings of starch-grains. 
Sketch all of the kinds examined, tak- 
ing pains to bring out the markings.! 
Compare the sketches with Figs. 10 
and 11. 
With a medicine-dropper or a very 
small pipette run in a very little iodine 
solution under one edge of the cover- 
glass, at the same time withdrawing a 
little water from the margin opposite 
by touching to it a bit of blotting-paper. 
Examine again and note the blue color- 
Fie. 10.—Starch-Grains stored in a ation of the starch-grains and the un- 
Cell in a Grain of Indian Corn. stained or yellow appearance of other 
substances in the field. Cut very thin 
slices from beans, peas, or kernels of corn; mount in water, stain as 
above directed, and draw as seen under the microscope. Compare with 
Figs. 10 and 11.2. Note the fact that the starch is not packed away 
1 The markings will be seen more distinctly if care is taken not to admit too much 
light to the object. Rotate the diaphragm beneath the stage of the microscope, or 
otherwise regulate the supply of light, until the opening is found which gives the 
best effect. 
2 The differentiation between the starch-grains, the other cell-contents, and the 
cell-walls will appear better in the drawings if the starch-grains are sketched with 
blue ink or a fine blue pencil. 
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