The method of procedure in mounting specimens for study varies according to the nature of the specimen, its preliminary treatment, and the character of the mount to be made. As to duration, mounts are either temporary or permanent.
TEMPORARY MOUNTS: In preparing a temporary mount, place the specimen in the center of a clean slide and add two or more drops of the temporary mounting medium, which may be water, or a mixture of equal parts of alcohol, glycerine, and water, or some microchemical reagent. Cover this with a cover glass and press down gently. Remove excess medium with blotting paper. Such mounts can only be used for short periods; when observation is finished, the slide should be washed.
PERMANENT MOUNTS: Permanent mounts are prepared similarly but use different mediums based on previous treatment of the specimen. If preserved in alcohol or glycerine and water, mount in glycerine jelly. Place a drop of mixture over powder, add glycerine jelly cube, heat to melt, mix carefully with needle, cover gently, label, and allow shrinkage before cleaning edges.
In mounting cross-sections, place the glycerine jelly at the side of the specimen rather than center. For specimens embedded in paraffin or collodion, use Canada balsam as medium. Cover glasses must be selected carefully based on manufacturer's standard thicknesses and types.
Key Takeaways
- Temporary mounts are used for short-term observation, while permanent mounts are prepared for long-term storage and reference.
- The type of mounting medium depends on the nature of the specimen and its previous treatment.
- Careful handling is essential to avoid air bubbles in permanent mounts.
Practical Tips
- Always use a clean slide and cover glass when preparing temporary or permanent mounts.
- When melting glycerine jelly, ensure it flows gradually over the specimen to replace air spaces.
- Labeling slides with detailed information helps organize your collection for future reference.
Warnings & Risks
- Do not stir glycerine jelly with a section during mounting; this can introduce air bubbles and damage the specimen.
- Permanent mounts in glycerine require careful handling as they are easily dislodged unless ringed properly.
Modern Application
While microscopy techniques have advanced, the principles of preparing temporary and permanent mounts remain foundational. Understanding these methods enhances the ability to study medicinal plants effectively, aiding in identification and research.
Frequently Asked Questions
Q: What is a suitable mounting medium for specimens preserved in alcohol or glycerine?
For specimens preserved in alcohol or glycerine and water, use glycerine jelly as the mounting medium.
Q: How should one handle air bubbles when preparing permanent mounts?
Pro Tip
If air bubbles are present during permanent mount preparation, heat a needle until it is white hot and touch the bubbles with its point to make them disappear.
Q: What is the recommended method for cleaning excess glycerine jelly from slides?
Important
After allowing shrinkage, clean edges by passing a knife blade around and under the cover glass to remove excess glycerine jelly.