after Debes - as communicated by Raymond Hummelink.

2gms of white film gelatine

75ml acetic acid

3 gm absolute alcohol or isopropanol

1.5 gm iso-butanol

1. Dissolve 2 grams of white film gelatine in 75 ml acetic acid; this can take several days. When dissolved filter. This stock solution can be stored in a refrigerator.
2. Mix 3 g absolute alcohol and 1,5 g Iso-butanol* and use a pipette to add, slowly, to 5 ml of the stock solution whilst stirring. This mixture should be stored dark and cool. 
3. A small drop of this mixture is applied onto a clean cover glass, using a glass rod or similar. The drop should spread pretty much to the edges on its own; no manipulation is needed. 
4. Gelatine for photography is to be preferred over food grade (supermarket) gelatine.
5. Only 0,7g of Iso-butanol can be used if preferred.

after Solliday - taken from Jim Sollidays paper

Gelatin-Acetic Acid-Ethyl Alcohol mixture 

Gelatin                    6 grams

Distilled Water        50 grams

Glacial Acetic Acid   50 grams

Ethyl Alcohal            8 grams

1. Place the Gelatin and Distilled Water in a 200ml flask, then place the flask in a hot water bath and agitate until the Gelatin is in solution. 
2. When cool add the Acetic Acid and Alcohol. Filter through filter paper, discarding the first few drops that pass through the filter. 
3. The fixative is stored in tightly stoppered bottles, filtered occasionally.                       

after Kemp

Gum Tragacanth

Absolute Alcohol

Glacial Acetic Acid

Glycerine

Distilled - deionised water

1. Dissolve Tragacanth in hot distilled water until thick to 1/3rd of the required final quantity.
2. Add an equal quantity of absolute alcohol and then the same of Glycerine and then filter.
3. Add Glacial Acetic Acid one drop at a time until it is just detectable to the nose.              

after Meakin - as communicated by Raymond Hummelink.

Meakin’s fixative: (Meakin, S.H., ”The Study of Diatoms”; IV: Selected Slides):

“A small supply of fixative must be made by dissolving half an ounce of Dextrine flour in a quarter ounce of water on a water bath and adding 1½ ounces of glycerine. When dissolved, preserve the fixative by adding about 3 per cent Carbolic Acid.”. 

An alternate fixative should be used!

Raymond Hummelink suggests using some glacial acetic acid and some sodium benzoate as a preservative instead of carbolic acid.

after AJ Doig - taken from Stuart R Stidolph's paper.

Egg albumen 50% and Glycerine 50%.

1. Mix together by stirring fresh egg albumen with an equal amount of glycerine. Filter through the fastest paper (Whatmans No. 1); change the filter paper regularly and pour remaining deposit from one to another. 
2. When the mixture becomes too thick for further filtration discard and proceed again with a fresh mixture until sufficient fixative is filtered (10ml is ample). Add 1% chlorbutol and the mixture will keep indefinitely.