Explain Procedure for the use of Light Microscope?

Now carry out the exercise following the steps enumerated herewith.

1. Place the microscopic slide with any specimen on the stage with the help of stage clips.  Move the slide to keep the specimen above the opening in the stage.

2. Adjust the light with the help of mirror and by adjusting the height of the condenser with the condenser knob. Iris diaphragm can be opened or closed to regulate the amount of light entering the condenser.

3. Rotate the scanning or low power lens into position. Lower the body tube to its lowest position and then raised slowly to bring specimen into focus with the coarse adjustment knob. Sharp focusing can be done with fine-adjustment knob.

4. Rotate the nosepiece to bring high power or oil immersion lens into position. For viewing fungal slide (i.e., Aspergillus), use high power lens (40x) and for bacteria (i.e., Bacillus) use oil immersion lens (100x). Because of parfocal nature of microscopes, minor focus adjustment can be done by using fine-adjustment knob.

As the magnification of lens increases, the distance between the objective lens and slide, called working distance decreases.  For oil immersion lens, a drop of oil is placed over the specimen before being used.

5. Scan the slide without the application of additional immersion oil.

6. After using microscope, clear all lenses with dry lens paper and use xylol to remove oil from stage.

7. Lower the body tube completely and place the low power objective in position.

8. Put the microscope back in cabinet.