84 
PRINCIPLES OF BACTERIOLOGY 
verting it over the glass slide—a very real danger, too, 
when handling virulent bacteria. 
If the bacteria have been grown on a solid medium, 
some growth should be taken from the culture tube with 
a platinum needle and emulsified with physiologic salt 
solution (0.8 per cent solution of NaCl) and a drop of 
this emulsion should then be transferred to the cover 
Fig. 15.— A, 
staining support with a gas burner underneath; B, staining 
bottles; C, Petri dishes. 
slip. The preparation is then ready for the microscopic 
examination. 
The main object to be accomplished by studying the 
bacteria in this way is to determine whether or not they 
are motile. 
II. Study of Bacteria in Stained Preparation 
*or this purpose a drop of fluid culture or a drop of 
bacterial growth emulsified in a little physiologic salt 
