20 LABORATORY BACTERIOLOGY 



is, do the individual bacteria move from one point in the field 

 to another? To determine this the centre of the drop is 

 better. Clearly distinguish between genuine motility and a 

 simple dancing motion (the Brownian movement). Deter- 

 mine the presence or absence of spores. These are bright, 

 highly refractive bodies either within or outside of the bodies 

 of the bacteria. If present, they can usually be seen in both 

 positions. Is there any evidence of a capsule around the 

 bacteria ? 



