PRACTICUMS 
1. Test ror StarcH.—The materials required for making the test 
below are inexpensive and may be obtained at a drug store. Each 
school should have on hand a few chemicals and glassware as a part 
of its regular laboratory equipment. Moisten some starch with 
diluted iodine. The starch will turn blue. If there is much starch 
present, the change will be a dark blue; if there is but little, the 
color will be a light blue. 
2, Test ror Grape Sucar.—Grape sugar or glucose may be tested 
as follows: Place a little corn syrup in a bottle or a test tube. Pour 
on it concentrated potassium hydrate and a few drops of copper sul- 
phate (blue vitriol) and boil. The mixture will turn green, yellow, 
orange and finally brick red. Test seeds for the presence of glucose. 
3. Trst ror CANE SucAr—Add a solution of cobalt hydrate (5 
grains of cobalt nitrate to 100 cubic centimeters of water) to the 
solution to be tested. Add to this a strong solution of sodium 
hydrate. A violet color indicates the presence of cane sugar. This 
test applied to grape sugar results in a blue color, which finally 
changes to green. 
4. Test ror Protein.—Reduce any common seeds to powder by 
pounding. Place in a test tube, add a few drops of nitric acid and 
boil. The protein will turn yellow. Add a few drops of ammonia 
and the protein will turn orange. 
Do the same with white of an egg. Chew several kernels of wheat, 
until the gluten becomes separated from the starch. The gluten is 
protein. Apply the same test as above. 
5. Test ror Fat or O1t.—Reduce seeds to a powder by pounding. 
Place the powder on a sheet of paper, lay on a piece of tin and, heat— 
not enough to burn the paper. If oil is present, a spot will be made 
on the paper. 
6. Bone AND MiNERAL Matrer.—Place a-slender bone in weak 
muriatic acid and another in a hot fire for a time, and note the 
effects. The acid will dissolve the lime, or mineral matter, out of the 
bone, and the fire will burn all grittle, or animal matter, out of the 
other. The first can be bent or even tied in a knot, while the latter 
is very brittle. 
(a) What gives toughness to bones? (b) What makes them 
hard and rigid? (c) Why may a child fall many times without 
breaking a bone, while an aged person is so apt to break one in 
falling? (d) At what time in life are bones most easily bent and 
made to grow in a wrong shape? (e) Would it injure an old per- 
son as much as it would a young child to sit long in a wrong position? 
?%. DeTERMINING Nutritive Ratto.—Process: (1) Reduce fat to 
its carbohydrate equivalent, (2) add the carbohydrates, and (3) 
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