Preparation of whole mounts
In whole mounts, the entire object is mounted for microscopic observation. This process is called whole mounting.
Whole mounting is of two types, namely temporary mounting and permanent mounting.
- 1) Temporary mounting: Temporary mounting is carried out for immediate observation. The slide cannot be stored for future use.
Temporary mounting is simple process. The object is cleaned, fixed, stained and mounted on a slide with a drop of glycerine.
2) Permanent Mounting: The permanent mounting is carried out for storing the slide for future use. It involves a series of steps called processing. The processing involves the fallowing steps
- Killing
- fixing
- washing
- Dehydration
- Clearing
- Staining
- Mounting
- Killing: If the material is alive, it is killed. Chloroform is mainly used for killing. In addition, alcohol, methanol, ether, etc. can also be used.
- Fixing: The material is fixed in a suitable fixative.
- Washing: The fixed objects are washed in water repeatedly to remove the fixatives.
- Dehydration: Dehydration is done by immersing the specimen in increasing concentrations of alcohol fallowed by benzene.
- Clearing: The stained material is dehydrated through a series of increasing concentrations of alcohol. The dehydrated section is cleared in xylol.
- Staining: The paraffin is removed with the help of xylol. When acidic stain is used, the section is rehydrated through decreasing concentraions of alcohol. The cytoplasmic proteins and carbohydrates are stained with acidic stains. The nucleus and chromosomes are stained with basic dyes. Lipids and steroids are stained with any one of the following dyes: Sudan dyes, fluorescent dyes, aqueous nile blue, rhodamine b and phosphine three R.
- Mounting: The sections are mounted on a glass slide containing an egg albumin coating.