PART II. 

 BACTERIOLOGICAL ANALYSIS. 



Culture Media. 



For a study of the general biological characters of 

 bacteria, growths in pure culture are required. For 

 this growth certain nutrient materials are necessary, the 

 nutrients varying more or less for the various species of 

 bacteria. For the pathogenic bacteria, media approxi- 

 mating to the nutrients of the body are most employed. 

 Desirable characters in culture media are clearness and 

 ease of preparation and sterilization. The methods of 

 preparation of the culture media in common use only, 

 will be given. 



Broth or Bouillon is much employed itself and as 

 the basis for nutrient jellies, as agar-agar and gelatine. 



One pound of lean beef-steak, freed from all fat and 

 connective tissue bands, is chopped up in a sausage 

 machine. 1,000 cc. of distilled water are added and the 

 meat is lightly boiled in a covered sauce-pan for § to 1 

 hour, occasionally being stirred. The mixture is filtered 

 through several layers of moistened filter paper and dis- 

 tilled water added to make up to 1,000 cc. Place this 

 in a flask containing 10 grammes peptone (Witte's or 

 Fairchild's), and 5 grammes of common salt, and steam 

 in sterilizer for J hour. 



