150 GENERAL MICROBIOLOGY 



EXERCISE 63. QUALITATIVE STUDY OF THE MICRO- 

 FLORA OF THE MUCOUS MEMBRANE (MOUTH 

 AND THROAT OR NOSE) 



Apparatus. Absorbent cotton, small piece; wire rod 

 about 15 cms. long; clean slides and cover-glasses; Petri 

 dish, sterile; tube of sterile agar; tube of sterile broth; 

 aqueous-alcoholic fuchsin. 



Method. I. For Teeth. 1. Place a small drop of dis- 

 tilled water on a clean cover-glass or slide. 



2. Introduce some material obtained by scraping along 

 the base of and between the teeth with a sterile platinum 

 needle. 



3. Allow to dry, fix and stain with aqueous-alcoholic 

 fuchsin. 



4. Examine microscopically with the oil immersion lens. 



5. Draw all forms seen. Would all of these forms 

 grow on an agar plate? Give reasons for your answer. 



II. For Throat or Nose. 1. Prepare a swab by winding 

 a small piece of absorbent cotton snugly about one end of 

 the wire rod. 



2. Place in a test tube, swab end down, and prepare 

 for sterilization as with pipettes. 



3. Dry-sterilize. 



4. Pour an agar plate and allow it to harden. 



5. Moisten the sterile swab in sterile broth, using 

 aseptic precautions, and then swab the throat or nose. 



6. Lightly brush the inoculated swab over the surface 

 of the agar plate and place the plate inverted, at 37, to 

 develop. 



7. Using the same swab, make a smear on a clean 

 glass slide, dry, fix, stain and examine as with the prep- 

 aration from the teeth. 



8. Return the swab to the tube of broth, incubate for 

 twenty-four hours and examine the growth in a hanging 

 drop. 



