Preservatives, Stains and Reagents

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A preservative is a chemical substance used to prevent decay, decomposition, or microbial growth in biological specimens. It helps maintain the structure and integrity of tissues for microscopic study…

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Bouin's fluid is composed of: - Saturated aqueous picric acid – 70 ml - Formalin (40% formaldehyde) – 25 ml - Glacial acetic acid – 5 ml It is a rapid-penetrating fixative used for histological prepar…

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Bouin's fluid penetrates tissues rapidly and provides excellent fixation of nuclear details without excessive hardening. It preserves fine cellular structures and is particularly effective for embryon…

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Carnoy's fluid consists of: - Absolute alcohol – 60 ml - Chloroform – 30 ml - Glacial acetic acid – 10 ml It is prepared fresh due to its instability and is highly flammable and toxic. It gives excell…

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FAA stands for Formalin-Acetic-Alcohol solution. Its composition is: - 50% alcohol – 100 ml - 40% formaldehyde – 6.5 ml - Glacial acetic acid – 2.5 ml It is an excellent general-purpose fixative that …

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A stain is a chemical substance used to color specific cellular components or tissues to make them more visible under a microscope. Stains help differentiate structures like nuclei, cytoplasm, or cell…

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Single staining involves using only one dye to color the entire tissue or cell. It highlights general morphology but does not differentiate between cellular components. Example: Acetocarmine stains bo…

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Double staining uses two different dyes to selectively color distinct parts of a cell. For instance, Methyl green stains the nucleus green, while Pyronin stains the cytoplasm pink, allowing clear diff…