598 LABORATORY EXERCISES 



LESSON (i 



Solid Vegetable Subslance (Fig. 210).- — These should consist of slant cylinders 

 (Fig. 211) in cotton-plugged test-tubes with some distilled water and steamed twenty 

 minutes at ioo°C. on each of three consecutive days or at the same temperature for 

 over an hour. Discontinuous sterilization is best. The following are some of the 

 vegetable substances recommended: 



1. Potato 7. Salsify 13. Peanuts 



2. Sweet potato 8. Parsnip 14. Brazil nuts 



3. Carrot 9. Onion 15. Apple 



4. Sugar beet 10. Tulip bulb 16. Pear, or quince 

 5 Turnip 11. Banana 17. Pineapple 



6. Radish 12. Coconut 18. Macaroni 



This list may be extended almost indefinitely. The method of preparation of 

 these solid vegetable substances for the test-tubes is fully described in Lesson 5. 



Oat Meal. — Put 10 grams of oatmeal in looo-c.c. Erlenmeyer flask. Add 200 

 c.c. of distilled water. Stir until thoroughly mixed and autoclave for twenty-five 

 minutes at i20°C. 

 Corn Meal. 



10 grams + 10 c.c. of water. 

 10 grams + iS c.c. of water. 

 10 grams + 20 c.c. of water. 



LESSON 7 



Plant Juices (With and without the addition of water). — Hay Infusion. 



1. Weigh out dried hay, 10 grams, chop it up into fine particles and place in a 

 flask. 



2. Add 1000 c.c. distilled water, heated to 7o°C. Close the flask with a solid 

 rubber stopper. 



3. Macerate in a water bath at 6o°C. for three hours. 



4. Replace the stopper by a cotton plug, and heat in the Arnold sterilizer at 

 ioo°C. for an hour. 



5". Filter through filter paper. 



6. Tube and sterilize in the Arnold sterilizer at ioo°C. for one hour on each of 

 three consecutive days. 

 Orange Juice. 



1. With a wooden, or metal lemon-squeezer remove the juice from one or several 

 oranges according to requirements. 



2. Filter through ordinary filter paper. 



3. Add to the test-tubes provided for the purpose. 



4. Plug the test-tubes with cotton. 



5. Sterilize on three consecutive days. 



