Schäfer’s Acid Logwood Solution is especially useful for certain structures, as tendon, cells, &c. It is thus prepared:—A 1 per cent. solution of acetic acid is coloured by the addition of 1·3 of its volume of logwood solution.
Schäfer’s Aniline Dyes, whether in aqueous or alcoholic solutions, give good results, and are prepared as follows:—Roseanilin or magenta (1 gr. to 1 oz. of alcohol), red; acetate of mauvein (4 gr., alcohol 1 oz., acid nitric 2 drops), blue; aniline black (2 gr., water 1 oz.), grey-black; Nicholson’s soluble blue (1-6 gr., alcohol 1 oz., and nitric 2 m.), blue. These stains should be used weak; and after sections are stained they should be passed through alcohol and oil of cloves as rapidly as possible; otherwise the colour will dissolve out before they can be mounted in balsam.
Schultze (Staining Bacilli).—Stain sections and cover-glass preparations for some hours in aqueous methylene blue solution, differentiate in 0·5 per cent. acetic acid, dehydrate in alcohol, clear in cedar oil, and mount in balsam.
Sclavo’s Stain for Flagella.—Leave the preparations for 1 minute in a solution of 1 Gm. of tannin in 100 C.c. of 50 per cent. alcohol; wash in distilled water; transfer for 1 minute to 50 per cent. phospho-molybdic acid; again wash, and stain for 3 to 5 minutes in a hot saturated solution of fuchsine in aniline water. Then wash in water, dry on filter paper, and mount in balsam.
Squire’s Picro-Carmine.—(1) Dissolve 1 Gm. of carmine with a gentle heat in 3 C.c. of strong solution of ammonia, and 5 C.c. of distilled water, then add 200 C.c. of saturated aqueous solution of picric acid, heat to boiling, and filter. (2) Dissolve 10 Gm. of carmine in a solution of 1 Gm. of caustic soda in 1000 C.c. of distilled water; boil, filter and make up to 1000 C.c. with water. Mix the solution with an equal quantity of water, and add 1 per cent. aqueous solution of picric acid so long as the turbidity produced disappears on agitation.
Squire’s Blueing of Sections.—After staining with hæmatoxylin, treat for a few seconds with a solution of sodium bicarbonate (1:1000) in distilled water.
Valentine (Fuchsine).—Ether shaken with a solution containing fuchsine is coloured violet after adding ferrous iodide, but not before.
Victoria Blue.—Victoria blue, 0·25 Gm.; rectified spirit, 20 C.c.; distilled water, 80 C.c.
Wedl’s Orseille or Orchella Stain.—Mix 5 C.c. of acetic acid, 20 C.c. of absolute alcohol, and 40 C.c. of distilled water; then add sufficient archil, from which excess of ammonia has been driven off, to form a dark reddish fluid.
Weigert’s Hæmatoxylin.—Dissolve 1 part of hæmatoxylin in 10 parts of absolute alcohol; then add 90 parts of distilled water and 1 part of aqueous solution (1:70) of lithium carbonate.