LABORATORY ACTIVITY FOR BIOLOGY
Palawan State University
Activity No. 2: Wet Mount (Wright Stain)
I. Materials
• Wright stain • Glass slides
• Lab gown • Cover slip
• Forceps • Blade
• Dissecting needle • Tissue
• Denatured alcohol • Leaves and stem of any plants
• Distilled water • Petri dish
• Microscope • dropper
, II. Procedure
General procedure:
1. Prepare everything that you need for the laboratory.
2. Use safety precautions in doing lab activity to avoid injury or damages.
3. Obtain the specimen by carefully using the blade to have a very thin slice of cross section of stem
and a lateral section of leaf to have a good result.
4. And use the lab materials for putting the specimens on the slides.
5. After obtaining the specimen and staining it, use cover slip.
6. Then view the specimen under the microscope.
For unstained specimen:
1. Using a dropper add one to two drops of distilled water to the center of the slide.
2. Add the specimen to this drop. Another drop of water may be added at this point if necessary
3. The specimen is then covered with a thin cover slip to exclude air and dust, and to protect the high
power microscope objectives. This is done by holding the cover slip by the edges, and then placing it
on the slide at an angle of about 45°so that the angle includes the specimen and the drop of water.
4. Gently and slowly lower the cover slip using a dissecting needle. If this is done with care and done
very slowly there should be few, if any, air bubbles trapped on the specimen or under the cover slip.
Air bubbles will be seen under the microscope as perfect circles with distinct dark edges.
5. Using extra water to irrigate slide. Add a drop of water to the side of the cover slip on the side away
from the bubble. Then apply absorbent paper to the edge of the cover slip near the bubble. Water
will be drawn across the slide and often the bubble moves with it. Raise the cover slip, add more
water and then lower it again. Tapping the cover slip very gently may release the bubble. Hopefully
the specimen is near the centre of the cover slip and the cover slip is close to the centre of the slide.
Carefully remove any excess water from the top and bottom of the slide. There should be NO water
on the top of the cover slip.
6. Look at the specimen under low power and if there are too many air bubbles in the specimen then
mount another specimen
7. If specimens begin to dry out then add a drop of water to the edge of the cover slip and draw it
under the cover slip, using the same method as staining a mounted specimen.
For stained specimen:
1. In staining, Place the slide on a small piece of paper towel
2. Add a drop of stain (wright stain) to the slide at the edge of the cover slip as shown
3. On the opposite side of the cover slip place a small piece of tissue or filter paper. This will draw the
stain from one side of the cover slip to the other and so through the specimen
4. Change the concentration of the solution under the microscope
5. Increase intensity of the stain by adding more stain
6. Add denatured alcohol.
7. Decrease the intensity of the stain by adding more water
8. Add water to a specimen that is drying out
9. See the effect that different solution concentrations have on cells etc.
Palawan State University
Activity No. 2: Wet Mount (Wright Stain)
I. Materials
• Wright stain • Glass slides
• Lab gown • Cover slip
• Forceps • Blade
• Dissecting needle • Tissue
• Denatured alcohol • Leaves and stem of any plants
• Distilled water • Petri dish
• Microscope • dropper
, II. Procedure
General procedure:
1. Prepare everything that you need for the laboratory.
2. Use safety precautions in doing lab activity to avoid injury or damages.
3. Obtain the specimen by carefully using the blade to have a very thin slice of cross section of stem
and a lateral section of leaf to have a good result.
4. And use the lab materials for putting the specimens on the slides.
5. After obtaining the specimen and staining it, use cover slip.
6. Then view the specimen under the microscope.
For unstained specimen:
1. Using a dropper add one to two drops of distilled water to the center of the slide.
2. Add the specimen to this drop. Another drop of water may be added at this point if necessary
3. The specimen is then covered with a thin cover slip to exclude air and dust, and to protect the high
power microscope objectives. This is done by holding the cover slip by the edges, and then placing it
on the slide at an angle of about 45°so that the angle includes the specimen and the drop of water.
4. Gently and slowly lower the cover slip using a dissecting needle. If this is done with care and done
very slowly there should be few, if any, air bubbles trapped on the specimen or under the cover slip.
Air bubbles will be seen under the microscope as perfect circles with distinct dark edges.
5. Using extra water to irrigate slide. Add a drop of water to the side of the cover slip on the side away
from the bubble. Then apply absorbent paper to the edge of the cover slip near the bubble. Water
will be drawn across the slide and often the bubble moves with it. Raise the cover slip, add more
water and then lower it again. Tapping the cover slip very gently may release the bubble. Hopefully
the specimen is near the centre of the cover slip and the cover slip is close to the centre of the slide.
Carefully remove any excess water from the top and bottom of the slide. There should be NO water
on the top of the cover slip.
6. Look at the specimen under low power and if there are too many air bubbles in the specimen then
mount another specimen
7. If specimens begin to dry out then add a drop of water to the edge of the cover slip and draw it
under the cover slip, using the same method as staining a mounted specimen.
For stained specimen:
1. In staining, Place the slide on a small piece of paper towel
2. Add a drop of stain (wright stain) to the slide at the edge of the cover slip as shown
3. On the opposite side of the cover slip place a small piece of tissue or filter paper. This will draw the
stain from one side of the cover slip to the other and so through the specimen
4. Change the concentration of the solution under the microscope
5. Increase intensity of the stain by adding more stain
6. Add denatured alcohol.
7. Decrease the intensity of the stain by adding more water
8. Add water to a specimen that is drying out
9. See the effect that different solution concentrations have on cells etc.
