CHAPTER V. 



BACTERIOLOGICAL TECHNIC. 



As may readily be supposed, the minuteness and wide distribution of 

 microbes call for special methods of study and examination. Even the 

 largest forms are far below the ken of unaided vision. Their general dis- 

 semination through organic substances calls for special methods for the 

 separation and isolation of individuals or of single bacterial cells. The 

 difficulties of technic are further increased by the resistance of spores to 

 various agents and substances which are readily fatal to higher organisms. 

 The methods of examination are also greatly complicated by the marked 

 polymorphism of many species. 



Bacteriological technic comprises the use of glassware, compound 

 microscope, and other apparatus, a thorough knowledge of sterilization and 

 disinfection, the preparation and use of culture media, the making of micro- 



FiG. II. — a, Nest of beakers and reagent bottles. The smaller and medium size 

 beakers are more desirable for bacteriological work. The reagent bottles are for Canada 

 balsam, stains, clearing fluid, etc. 



bic cultures, and the study of cultures. Methods vary greatly. The follow- 

 ing represents a brief summary of general methods which are noted for 

 simplicity and which have proven very satisfactory after years of testing. 



I. Cleaning the Glassware. 



All glassware, such as test-tubes, flasks, beakers, Petri dishes, pipettes, 

 shells, bottles, etc., which is to be used in bacteriological work must be clean; 

 that is, free from all extraneous organic as well as inorganic matter. To 

 accomplish this, it is necessary to use an abundance of pure water, hot as 

 well as cold, aided by sand, paper shreds, brushes, towels, alcohol, acids, 

 soap, sodic and potassic hydroxides, and whatever else may be necessary. 

 Boil, wash, rinse, and wipe within and without repeatedly until it looks, and 



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