BACTERIOLOGY 



ted by simple introduction of a small mass of bacteria and mixing 

 them with the medium. At the same time it is well to make a 

 smear preparation from the colony and to stain with one of the 

 aniline dyes so as to determine the morphology of the bacteria. 

 The growths which take place in the tubes should contain one 

 and the same kind of bacteria. As seen under the microscope 

 these bacteria should have the same general form and appearance 



FIG. 44. Stab-culture. 



A rubber stopper may 

 be used to prevent drying, 

 see page 121. 



FIG. 45. Smear-culture. 

 This tube shows the 

 rubber cap used to prevent 

 drying. 



as those seen in the colony from which they were derived. This 

 will be the case, provided the colony has resulted from the develop- 

 ment of a single bacterium. 



A pure culture is a culture which contains only the descendants 

 of a single cell. 



Stock Cultures. To maintain their vitality bacteria need to 

 be transplanted from one tube to another occasionally; the time 



