Freezing medium Freeze sectioning requires a mounting medium to prevent the material from freezing in a form that is too brittle to section. Hamilton's freezing solution is based on sucrose and gum Arabec, which allows some elasticity if it is not frozen to too low a temperature. The stock solution should be kept in a refrigerator. This allows some of the moisture under the coverslip to moisten the harder material at the edge of the coverslip when the warmer is switched off, and this evaporates away when the warmer is switched on. This gradually draws away excess moisture from under the cover slip, and hardens the medium over a period of 1-2 weeks.
Aniline blue is the stain which gives the quickest results.
Make up a densely coloured, but not saturated solution of water soluble aniline blue, and keep it in a dropper bottle. Transfer sections from the microtome blade using a fine sable hair brush, and orient them gently under a dissection microscope before adding a coverslip. It works best if the specimen can be soaked for 1-5 hours in a watch glass after it has been decalcified but before sectioning. Then add one drop to the slide an prepare as noted for aniline blue above. This stain can also be used for paraffin or epoxy sectioning.