Quarterly Journal of Microscopical Science, Vol s3-88, 123-133, Copyright © 1947 by Company of Biologists

Ester Wax: A New Embedding Medium

¹ Department of Zoology, The University, Glasgow

Ester wax is a new ribboning embedding medium. It consists of five substances which may be varied in proportion so that media of different characteristics may be produced. A mixture which will meet most requirements is as follows:

Diethylene glycol distearate . 73 gm.

Ethyl cellulose . . . 4 gm.

Stearic acid . . . . 5 gm.

Castor oil . . . . 8 gm.

Diethylene glycol monostearate . 10 gm

The following facts relate to this mixture:

Melting-point. 46-8° C.

Section range. 2-20 µ at a room temperature of 64° F.

Ribbon range. 2-15 µ at a room temperature of 64° F.

Final compression loss. 7.6 per cent, at 10µ (after flattening).

Solvents. Alcohols, ethers, esters, ketones, hydrocarbons, aldehydes, chlorinated hydrocarbons, natural oils, &c.

Cutting. This must be done more slowly than with paraffin wax.

Flattening. Sections may be flattened on tap-water or aqueous staining solutions. Flattening must be completed in a drying oven at 40-50° C. with sufficient water under the sections to float them.

Staining. Two methods: (1) In the ribbon; (2) As for paraffin wax sections. Pre-mounting fluid. Xylene, benzene, ligroin, &c.

Mounting fluid. ‘Sira’, or Kirkpatrick and Lendrum's polystyrene mounting medium.