REAGENTS

All staining reagents should be kept in well-closed glassstoppered bottles (except Loeffler's methylene blue) and protected from direct sunlight. For frequent use, flexible plastic bottles with tube outlets may be used but they must be washed out thoroughly before refilling. They should not be stored in close proximity to concentrated acids or ammonia. Distilled water for reagents should be freshly prepared and neutral in reaction.

Formulae of staining reagents are listed in alphabetical order.

Acetone – iodine solution for decolorization

Strong iodine solution

Dissolve the iodine and potassium iodide in the water and adjust to volume with the ethanol.

Mix well before use

Acid-alcohol

Mix well before use.

Albert's stain

Dissolve the dyes in the ethanol. Mix the acid with the water and add to the dye solution. Allow to stand for 24 h and then filter.

Ammoniacal silver nitrate solution

Dissolve the nitrate in the water; to 90 ml of this solution add strong ammonia solution (sp. gr. 0.880) drop by drop until the precipitate which forms just dissolves; add sufficient of the remaining AgNO3 solution drop by drop until the reagent remains faintly turbid even after shaking. When protected from light, this reagent is stable for several weeks.

Ammonium oxalate – crystal violet stain

Mix and dissolve.

For use, mix 20 ml of solution A and 80 ml of solution B.

Aqueous solutions

Simple aqueous solutions of each of the following are used in staining.