Hot Celloidin Technic 75 



Hold one of these against the under surface of the knife and slip the 

 section off onto the paper. Invert the section and paper in a dish of 

 70% alcohol and press them down against the bottom of the dish. The 

 sections can be stacked one on another in this fashion and stored until 

 they are stained. Caution: use plain white paper, filter paper or paper 

 towels. Lined paper may stain the nitrocellidose and produce poor 

 staining. 



Method 2. An alternate method is to flood the knife with alcohol and 

 moisten a camel hair brush. Hold the brush close to the nitrocellulose 

 block, so the alcohol is held between the block and brush by capillary 

 action. Do not rest the brush too firmly on the block, lest it be cut by 

 the knife. Pull the knife across the block; raise the brush slightly, and it 

 will gtiide the section onto the knife, smoothly and withotit rolling. 

 Remove as above. {Walls, 1932) 



Method 3. Walls (1936) developed a dry method which eliminates 

 the constant soaking with alcohol during sectioning. After the block is 

 hardened, soak it in cedar oil: chloroform (50:50) for 24 hotirs. Blot the 

 block and allow it to stand in the air for 10-20 minutes. Transfer to 

 cedar oil; this Itibricates the block and knife dtiring sectioning. The 

 sections, as removed from the knife, are placed in the same kind of oil, 

 then rinsed in 95% alcohol, 80% alcohol, and transferred to water for 

 staining. This type of oil-soaked block can be sectioned on a rotary 

 microtome as well as a sliding one. 



Hot Celloidin Technic 



Koneff (1937) Method 



This is a more rapid method and can be used when materials are not 

 injured by heat. The procedures are handled in screw-cap jars in a par- 

 affin oven, about 56°C. 



1. 70% alcohol, 2 changes: | hour each. 



2. 80%, alcohol, 2 changes: ^ hour each. 



3. 95% alcohol, 2 changes: | hotir each. 



4. Absolute alcohol, 2 changes: ^ hour each. 



5. Absolute alcohol-ether (equal parts): 1 hour. 



6. 10% nitrocellulose: 1 hour. 



7. 25-33% nitrocellulose: overnight. 



8. Embed as for rapid cold method. 



