THE STUDY OF THE GROWTH OF BACTERIA 1 07 



teria, exhibits tiny little dots, or colonies (pure cultures) growing 

 discretely isolated. By means of a sterilized platinum needle these 

 little colonies may be fished out and transplanted to fresh culture 

 tubes, and after a few hours' growth they become pure cultures. 



FIG. 30 Series of stab cultures in gelatine, showing modes of growth of different 

 species of bacteria. (Abbott.) 



An old method employed in many laboratories, in breweries and 

 originated by Pasteur was what is known as the dilution method. 

 Numerous flasks are inoculated by matter containing bacteria 

 very highly diluted in bouillon and by means of a sterile 



