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Hint
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Answer
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Not suitable for routine purposes because it is expensive
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clove oil
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If tissue or section is incompletely dehydrated, it becomes milky
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xylene
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It acts slower than benzene and is expensive
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Toluene
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Clearing time of benzene
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15-60 minutes
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Substitute to xylene or benzene
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toluene
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It is not carcinogenic but highly concentrated emit fumes that are toxic upon prolonged exposure
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Toluene
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Carcinogenic or may damage bone marrow (Aplastic anemia; If antibiotic: Chloramphenicol)
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benzene
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It is the best of the traditional clearing agents for routine use
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chloroform
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It becomes milky on prolonged storage
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cedarwood oil
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Gives the widest latitude
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chloroform
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Usual clearing time of xylene
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1/2-2 hours
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Quality is not always uniform and good and is extremely slow
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cedarwood oil
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It causes considerable hardening and shrinkage of tissues; hence, is not suitable for nervous tissues and lymph nodes.
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xylene
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An excellent and true clearing agent
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xylene
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These are slow-acting clearing agents that can be used when double embedding techniques are required.
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Methyl benzoate
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clearing time of cedarwood oil
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2-3 days
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Best for nervous tissue, lymph nodes, granulation tissue, and fetal and other delicate, highly cellular specimens, all of which tend to become distorted and to break up on sectioning if cleared in xylene, toluene, or benzene
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chloroform
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Highly flammable
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xylene, benzene
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It removes aniline dyes and dissolves Celloidin; Tissues become brittle
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clove oil
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It does not make tissues transparent and it is toxic to the liver (hepatotoxic) after prolonged inhalation
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chloroform
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Toxic on prolonged exposure
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CCl4
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Causes minimum shrinkage of tissues
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clove oil
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Properties are very similar to chloroform but it is cheaper
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CCl4
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Clearing time of toluene
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1-2 hours
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Dehydrates and clears at the same time since it is miscible in both water and paraffin
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Tetrahydrofuran
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Recommended for CNS tissues and cytological studies (esp. Smooth muscles and skin)
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cedarwood oil
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It is slower in action than xylene, but causes less brittleness
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chloroform
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The most rapid clearing agent
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xylene
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It is recommended for tough (skin, fibroid and decalcified tissues) and large tissue specimens
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chloroform
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Cheap and does not extract out aniline dyes
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xylene
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Its quality is not guaranteed due to its tendency to be adulterated
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clove oil
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Can be used with celloidin sections
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xylene
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It is miscible with absolute alcohol and paraffin
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xylene, toluene, benzene
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Recommended for clearing embryos, insects and very delicate specimens since it clears 70% alcohol without excessive tissue shrinkage and hardening
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aniline oil
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Rapid acting, recommended for urgent biopsies and routine purposes
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30-60 minutes
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Clears both Paraffin and Celloidin sections
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cedarwood oil
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Block size for xylene
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<5 mm
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clearing time of chloroform
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6-24 hours
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Urgent biopsy clearing time of xylene
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15-30 minutes
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Very expensive and it requires 2 changes in clearing solution
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cedarwood oil
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