PART II. MEDICAL BACTERIOLOGY. 

 CHAPTER VI. 



PATHOGENIC AEROBES. 



EXERCISE LXXIV. PREPARATION OF CULTURE MEDIA. 



The following media will be necessary for the work outlined in the following chap- 

 ters. This is exclusive of a few special media which are described under special heads 

 and are to be performed as a part of the exercise in which they are used. 

 100 tubes of agar. 



12 tubes of glucose agar. 

 100 tubes of gelatin. 



12 tubes of glucose gelatin. 



30 tubes of bouillon. 



30 fermentation tubes of glucose bouillon. 



30 tubes of potato. 



30 tubes of milk. 



30 tubes of glucose free broth or Dunham's solution. 



30 water blanks. 



30 tubes of blood serum : 



a. Collection of the blood. Sterilize Mason fruit jars, by successive washings in 

 corrosive sublimate, distilled water, alcohol and ether (or sterile Erlenmeyer flasks may 

 be used) . These are to be carried to the slaughter house and the blood from a beef caught 

 directly into them . They are then allowed to stand undisturbed for 15-30 minutes, or 

 until the clot has firmly attached itself to the sides of the vessel, when they may be 

 removed to the laboratory. 



6. Separation of the serum from the blood clot. The clot is separated from the 

 sides of the vessel by means of a sterile knife or glass rod, and the vessel placed in the 

 ice chest. After standing 48 hours the clot will have shrunken away from the walls of 

 the vessel leaving the clear serum on the top and at the sides. This can now be pipetted or 

 siphoned off. If the serum contains a large number of red blood corpuscles it can be 

 placed in rather tall cylinders (graduates) and allowed to stand 24 hours longer, when 

 the clear straw -colored serum can be readily separated. This may be preserved for a 

 long time by the addition of i % chloroform and kept in a tightly corked bottle in a 

 cool place. 



c. Loeffler's mixture. This consists of 3 parts of blood serum and 1 part of glu- 

 cose bouillon ( 1 % ) . 



d. Sterilization. Fill sterile test-tubes (about 3 cm. deep) with the serum and ster- 

 ilize either: 



