A practical course in botany : with especial reference to its bearings on agriculture, economics, and sanitation . Fig. 12. — Starch grains of wheat indifferent stages of disintegration under theaction of a ferment (diastase), accompany-ing germination : a, slightly corroded ; h, c,and d, more advanced stages of decomposi-tion. PRACTICAL COURSE IN BOTANY. THE SEED 9 Experiment 3. To show the presence of starch. — Put a drop ofiodine solution on some starch. What change of color takes place ? Tomake iodine solution, add to one part of iodine crystals 4 parts potas-sium iodide and 95 parts water
A practical course in botany : with especial reference to its bearings on agriculture, economics, and sanitation . Fig. 12. — Starch grains of wheat indifferent stages of disintegration under theaction of a ferment (diastase), accompany-ing germination : a, slightly corroded ; h, c,and d, more advanced stages of decomposi-tion. PRACTICAL COURSE IN BOTANY. THE SEED 9 Experiment 3. To show the presence of starch. — Put a drop ofiodine solution on some starch. What change of color takes place ? Tomake iodine solution, add to one part of iodine crystals 4 parts potas-sium iodide and 95 parts water. It should be kept in the dark, as lightdecomposes it. Iodine colors starch blue, protein substances light testing for starch, the solution should be diluted till it is of a pale color,otherwise the stain will be so deep as to appear black. Experiment 4. A test for proteins. — Place a small quantity ofthe white of an egg, diluted with water, in a clean glass and add a fewdrops of nitric acid; or drop some of the acid on the white of a hard-boiled egg. What is the effect ? Nitric acid turns proteins yellow; if the color is indistinct, add a dropof ammonia, when an orange color will ensue. Experiment 5. Another test for proteins. — Place on the sub-stance to be examined a drop of a saturated solution of cane sugar andwater; add a dro
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