8 
Exercise 3. Examination of Stained Dead Bacteria 
MATERIALS: 
Prepared slides of the principal morphological types of stained, 
dead bacteria. 
1. Adjust the microscope as before. See that the diaphragm is completely 
open and the lighting is even. 
2. Place the slide of stained or dyed specimens of dead bacteria upon the 
stage of the microscope. 
3. Examine preparation A with the 16 m. m. objective. 
(a) Is there any detail or anything definite to be seen? 
(b) Draw what can be seen. 
FIG. 5-FORM AND ARRANGEMENT OF THE LOWER BACTERIA 
A, spheres; B, rods; C, spirals 
4. Examine the same preparation with the 4 m. m. objective. 
(a) What can be seen? 
( b ) Draw a few of the objects seen. 
Make the drawings large enough to show the exact shape of 
the objects and much larger in proportion to the size of the 
stencil than the objects bear to the microscopic field. 
5. Raise the tube until the 4 m. m. objective is not less than 4 m. m. above 
the object. Place a small drop of immersion liquid on the center of the cover 
glass. Revolve the oil immersion objective into place. Carefully lower it, 
watching from one side, until the lens of the objective is immersed in the oil 
and almost touches the object. 
