SECTION THREE 



2. Transfer the tissue to a mixture of any of the above solvents 

 and polyester wax, or directly into the pure wax. 



Note: The infiltration time recommended by the author 

 (Steedman) is approximately one third longer than that for 

 paraffin wax. 



3. Cast the block, as with paraffin wax: do not immerse the 

 wax in water, but leave it to cool in the atmosphere. It is not 

 necessary to surround the block with cold water. 



4. Cut sections at the speed of paraffin section (about 80-100 

 per minute). Do not handle the block. 



5. Float the sections or ribbons on to the amylopectin adhesive, 

 either on a microscope slide or in a dish. 



6. Flatten the sections by leaving them on the amylopectin 

 solution for five to ten minutes at room temperature (18° C), or 

 by placing the slide with the amylopectin and the section on it, 

 on a warm plate for about thirty seconds. 



7. Carefully draw off the excess amylopectin solution from the 

 slide, then leave the section to dry at room temperature overnight. 



Note: It is essential that the excess amylopectin solution is well 

 drained off the slide before drying, as otherwise amylopectin will 

 show as fine black dots under the microscope. 



8. Carry the sections through to water, as in the case of paraffin 

 sections, then stain, dehydrate, clear and mount as usual. 



Notes: 



[a) The wax has a melting point of 37° C. 



{h) The author (Steedman) claims that the main advantage of 

 his polyester wax over paraffin wax, his earlier ester wax (Steed- 

 man, 1947), and Chesterman & Leach's (1956) modification of 

 the latter, is its low melting point which reduces hardening and 

 shrinkage of tissues as well as obviating other heat-induced 

 artefacts. 



{c) Heavy, not readily volatile solvents such as cedarwood oil 

 are not recommended for use with polyester wax. However, 

 alcohols, ethers, and esters are recommended, as well as aromatic 

 hydrocarbons such as xylol and benzene, for those who prefer 

 them. The author states that 96% alcohol is excellent. 



[d) All the known adhesives for tissue sections failed to prevent 

 the loosening of polyester wax sections from slides, and of more 



