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Preservation of other animals specimens
(a) Chemical method – Preservatives are used in which the animal specimen can be stored . These method is used especially for large animals which cannot be easily dried
Qualities of a good preservative
(a) Should not change the chemical composition of the organism store or preserved
(b) Should have a fair pleasant smell
(c) Should be colourless
(d) Must not be reactive to the user
Examples of common preservatives
(a) Formalin /formaldehyde – it is usually sold at 40% from which different solutions can be made. The recommended dilutions for common animals are
Fish – 10%
Amphibians- 3.5%
Reptile’s -5-10 %
Birds -15%
Mammals 10%
Advantages of formalin
- Cheap and available
- It hardens the organs
Disadvantages –
- It has a nasty smell
- Some people are allergic to it
- It is slightly dangerous to animal skin
- It is acidic and decomposes bones
- Buffered alcohols – any of the alcohol that exist as liquid at room temperature can be used as a preservatives e.g. methanol , pentanol , hexanol , propanol , heptanol. The most common dilution of alcohol is 70%
Advantages of alcohol
- Have no abnoxious smell
- Some are odorless
- Not associated with any allergy
Disadvantages of alcohols
- It causes shrinkage of tissues due to dehydration
- Some are expensive
- Does not harden the organism
Procedure followed in chemical preservation
(a) Put the organism in a suitable container.
The container should be;
– Of appropriate size
– Have wide mouth
– Be transparent
(c) Chose the preservative required and make necessary dilution. The preservative should completely cover the specimen
(d) Close tightly the lead and label
NB/ Alternatively the organism may be injected with the preservative . these process of injecting the preservative into the organism is called embalming.
(e) Fixation procedure should be followed