Staining, Histochemistry and Histotechnology
(Frequently Asked Questions)
Dr. John A. Kiernan
Department of Anatomy
and Cell Biology
The University of Western Ontario
mounting medium and variants
Where can I find the recipe to make von Apathy's mounting medium? Is there more than one way to make it?
Von Apathy's medium is simple to make and lasts well so it would be very straightforward to make yourself.
Von Apathy's Gum Syrup medium, RI 1.52
Dissolve 50 grm gum arabic (gum acacia) and 50 grm cane sugar in 50 ml of distilled water with frequent shaking in a 60 degree water bath. Add 50mg of thymol (or 15mg Merthiolate)
as a preservative. If too thick for your application increase
the amount of distilled water.
While warm put in a vacuum chamber to remove air bubbles.
To prevent "bleeding" of metachromatic staining of amyloid by methyl or crystal violet, add 30 to 50 grm of potassium acetate
or 10 grm of sodium chloride.
This mounting medium sets hard and there is no need to seal the coverglass.
You will find the recipe, only it is called Apathy's gum syrup, in Histopathologic Technic and Practical Histochemistry, edited by RD Lillie & HM Fullmer (3rd edition, 1976, page 101). The recipe given is Lillie and Ashburn's modification. Ref: Arch Pathol 36:432 1943. It was Highman who modified the medium by adding potassium acetate and sodium chloride. Ref: Arch Pathol 41:559 1946.
RAB Drury and EA Wallington also mention Highman's variant in the excellent book, "Carleton's Histological Technique," 4th ed. London: Oxford University Press, 1967.
John Kiernan, London, Canada
Ian Montgomery, Glasgow, Scotland