10 PRACTICAL COURSE IN BOTANY 



Experiment 9. To show that diastase converts starch into 

 SUGAR. — Make a paste of boiled starch so thin that it looks like water. 

 Pour a small quantity of it into each of two tubes, adding a little diastase 

 to one and leaving the other untreated. Keep in a warm place for twenty- 

 four hours, then test both tubes for starch, as directed in Exp. 3, and note 

 the result. If the diastase has not acted, add a little more and watch. 



Practical Questions 



1. Name all the food and other economic products you can think of 

 that are derived from the seed of maize; from wheat; from flaxseed; 

 from cotton. 



2. Mention some seeds from which medicines are procured. 



3. Name all the seeds you can think of from which oil is obtained ; 

 starch; some that are rich in proteins. (Exps. 1-5.) 



4. Describe some of the ways in which these products are frequently 

 adulterated. 



5. If you were raising corn to sell to a starch factory, what part of 

 the seed would you seek to develop ? If to feed stock, what part ? Why, 

 in each case? (3; Figs. 4-7.) 



6. What grain feeds more human beings than does any other ? 



7. Name all the seeds you can think of that contain sugar in sufficient 

 quantity to be detected without chemical tests ; that is, by tasting alone. 



8. Is "coal oil" a mineral or an organic substance? Explain, by 

 giving an account of its origin. 



9. What is gluten ? (3.) Name some grains that are especially rich in it. 

 10. Which of our three chief food grains is a water plant ? (See Plate 



2.) Which grows farthest south ? Which farthest north ? Which one is 

 of American origin ? 



n. SOME PHYSIOLOGICAL PROPERTIES OF SEEDS 



Material. — Seeds of squash, pumpkin, or other melon; castor bean ; 

 any kind of common kidney bean ; grains of Indian corn. 



Appliances. — In the absence of gas, an alcohol or kerosene lamp may 

 be used for heating. A double boiler can easily be made by using two tin 

 vessels of different sizes. Partly fill the larger one with water, set in it 

 the smaller one with the substance to be heated, and place over a burner. 

 A pair of scales, a strong six-ounce bottle, wire-netting, cord, and wax 

 or paraffin should be provided. 



Experiment 10. Do seeds in their ordinary quiescent state 

 CONTAIN ANY WATER? — Placc a number of beans, or grains of corn or 

 wheat in a glass bottle, making a small perforation in the cork to allow 

 the air to escape, and heat gently. Does any moisture form on the glass ? 



