54 LABORATORY GUIDE IN BACTERIOLOGY 



Make a sketch of part of a field under the 

 microscope. 



II. Plate cultures. 



1. Naked-eye appearance. 



a) Surface colonies. 



If colonies are too small to make observations with 

 the naked eye, this fact should be stated. 

 Color by reflected light, 

 Approximate size. 

 Elevation or depression. 

 Translucency. 

 Moist appearance. 

 Smoothness. 

 Luster, 



Liquefaction (in gelatin plates only). 

 Consistency: soft, viscid, hard, chalky. 



b) Deep colonies. 

 Color. 

 Shape. 



2. Microscopic appearance under low power 

 (No. 3 objective, Leitz). Use little light; 

 the diaphragm should be almost closed. 

 a) Surface colonies. 



Shape. 

 Color. 



Translucency. 



Thickness (in center and edges). 

 Nucleation. 

 Striation. 



Granulation (if present, whether coarse 

 or fine) or Homogeneity. 



