CHAPTER IX. 



THE MICROSCOPIC AND CULTURAL STUDY OF 

 BACTERIA. 



METHODS FOR THE MICROSCOPIC STUDY 



OF BACTERIA. 

 I. LIVING BACTERIA. 



A. Hanging Drop. 



B. Hanging Block. 



C. Dark Ground Illumination. 



D. Intra Vitam Staining. 

 II. STAINING OF BACTERIA. 



A. Chemistry of Stains. 



B. Preparation of Stains. 



C. Technio of Staining Bac- 



teria. 



D. Intensive Stains for Bac- 



teria. 



E. Stains for Special Struc- 



tures of the Bac- 

 terial Cell. 

 1. Spores. 



2. Capsules. 



3. Polar Bodies. 



4. Flagella. 



F. Differential Stains for Bac- 

 teria. 



1. Gram. 



2. Ziehl-Neelsen. 



3. Gabbett. 



4. Polychrome Stains. 



5. Smith Sputum Stain. 



III. STAINING BACTERIA IN TISSUES. 



IV. METHODS AND MEDIA FOR THE 



CULTIVATION OF BACTERIA. 

 V. CULTIVATION OF BACTERIA. 

 Inoculation of Cultures. 

 Isolation of Pure Cultures. 

 Incubation of Cultures. 

 VI. STUDY OF BACTERIAL CULTURES. 



METHODS FOR THE MICROSCOPIC STUDY OF BACTERIA. 



BACTERIA may be examined directly under the higher powers of the 

 microscope for their morphology, motility, arrangement, method of 

 reproduction, and their behavior in specific sera, or they may be 

 stained with various anilin dyes and chemicals to bring out details 

 of structure or composition, and their relation to various tissues in 

 pathological processes. 



Glass slides and cover-glasses are conveniently used for this purpose. 

 Microscopic slides should be made from clear, colorless glass. Cover- 

 glasses should be made of thin glass. The available working distance 

 of oil-immersion lenses is somewhat less than 1.5 mm., consequently 

 cover-glasses should not measure more than 1 mm. in thickness as 

 a maximum limit. Number 1 cover-glasses are suitable for bacterio- 

 logical work. 



Glass slides and cover-glasses are best cleaned in a mixture of 

 potassium bichromate, 1 part; water, 4 parts; sulphuric acid, 6 parts. 

 The bichromate is dissolved in the water with the aid of heat and 

 cooled; the acid is added slowly with constant stirring. Immersion 

 in this mixture for twenty-four hours removes dirt and grease from 



