CHAPTER IV 



METHODS OF STUDYING MICROORGANISMS 

 -STERILIZATION BY HEAT 



LABORATORY TECHNIQUE 



IN the study of microscopic beings, it has been 

 necessary to elaborate a special technique which will 

 supply the requirements of life. Before the epoch- 

 making work of Koch it was necessary to cultivate 

 microorganisms upon broth or bread, and there w y as 

 little known as to the exact composition of the medium. 

 Koch showed how to control the growth of bacteria 

 in the laboratory. To Pasteur and Kohn also is due 

 credit for the standardizing of the foodstuffs upon 

 which bacteria are cultivated. Let us assume that' we 

 have been given a culture of bacteria to study. Since 

 the identification of species is not a part of a nurse's 

 duty it is not necessary to discuss the separation of 

 many germs in a mixture. Bacteria are transferred 

 from one place to another, as, for example, from one 

 culture tube to another or to a glass slide by means of 

 a piece of platinum wire set into a handle. This metal 

 will withstand great heat and can be sterilized in the 

 flame of a Bunsen burner after every using. The 

 Bunsen burner is an apparatus so arranged that air is 

 thoroughly mixed with the gas and the mixture is 

 completely burned, Starting out with the material 



