L/VEOJ^ATORY AND TEACHING METHODS 



587 



2. Turn in the ends neatly and rull the strip of wool lightly between the thumb 

 and fingers of both hands to form a long cjdinder. 



3. Double this at the center and introduce the now rounded end into the mouth 

 of the tube or flask. 



4. Now, while supporting the wool between the thumb and fingers of the right 

 hand, rotate the test-tube between those of the left, and gradually 



screw the plug of wool into its mouth for a distance of about the r?='*^=^ 



same length of wool projecting. "' * ' 



The plug must be firm and fit the tube or flask, but not so 

 tightly that it cannot be removed by a screwing motion when 

 grasped between the fourth, or third, and fourth fingers and the 

 palm of the hand. 



Rough Method of Cultivating Bacteria and Fungi.— 1. Make 

 decoctions of split peas, cabbage, lettuce, hay, lima beans, broad 

 beans and water lily leaves by boiling in water. Expose decoc- 

 tions to air by placing in an open vessel. This gives the 

 organisms introduced from the air. 



2. Boil a similar lot of material in a glass flask over a water 

 bath. After material is thoroughly steamed, close opening of the 

 flask with a cotton plug. Note result. 



3. Place untreated material in distilled water previously 

 boiled. Plug the flask with cotton. This wiU serve as a control. 

 This gives the organisms introduced on the material. 



Desiderata. — Flasks, cotton, water bath and Bunsen burner for 

 these experiments will be found in the Culture Room. Perform 

 all experiments there. 



Other Materials. — Procure a loaf of dry bread, cut it into 

 slices and place slices on a dinner plate. Wet bread until well 

 soaked with water, cover -with a bell jar provided with wet filter 

 paper. 



Fig. 



209.- 



Similarly take horse manure, wet it and place under a bell ^Jl °^ plugged 

 jar. Place jars in a dark place 



with 



Inoculate the following culture potato slant rest- 

 media with the spores of the various fungi that grow on the bread ing on a bit of 

 and manure. For this purpose, use a platinum needle sterilized ^lass rod to keep 



in the Bunsen flame. 



Culture of Slime Moulds.- 



-Compare: The Culture of Did- 



ymitim xanlhopus (Ditmas) Fr. in Synthetic Media, Science, new tube , 



XL: 791, Nov. 27, 1914. 



LESSON 3 



the potato out of 

 the water in the 

 bottom of the 

 {After 

 Williams, in 

 Schneider, Phar- 

 maceutical Bac- 

 teriology, p. 54.) 



Microscopic Study of Culture Material. — A study is to be made 

 of the organisms raised in the culture media prepared as directed in Lesson 2. 



Hanging-drop Preparation. — i. Smear a layer of vaseline (sterile) on the upper 

 surface of the ring cell of a hanging-drop slide by means of the glass rod provided 

 with the vaseline bottle, and place slide on a piece of filter paper. 



