igo PRACTICAL BACTERIOLOGY. 



developed into longer or shorter threads, whichj as 

 a rule, are much entangled and twisted together. 

 Small portions of the blood can be spread upon cover- 

 glasses for future staining. 



In order to prepare a pure culture, we proceed in 

 the usual manner. A small portion of blood is well 

 mixed in a test-tube with some fluid gelatine. From 

 this one a second, and from the second a third tube 

 full of gelatine is inoculated in the usual way. The 

 contents of the third test-tube are then poured out on 

 to plates, which, after the gelatine has solidified, are 

 placed in an incubator, which is kept at a temperature 

 of about 20° C. 



On the next day, very small whitish points are 

 visible with the naked eye. By the day after that 

 these points have developed into whitish spots, of 

 about one millimetre in diameter, the outlines of 

 which are indistinct and wavy, becoming imper- 

 ceptibly merged in the gelatine. 



Even with the naked eye it can be seen that the 

 colonies are not quite homogeneous. If one of them 

 be examined with a low power of the microscope 

 ( X 50-80) a most characteristic appearance immedi- 

 ately presents itself by means of which the anthrax 

 bacillus can be both easily and surely distinguished 

 from all other kinds of bacteria. Peculiar wavy strings 

 of bacterium threads can be seen twisted backwards 

 and forwards in every direction. No isolated bacilli 



