Benda’s Copper Hæmatoxylin.—Harden the material with chromic acid or Flemming’s solution and leave sections for 24 hours in a 5 per cent. solution of neutral copper acetate at a temperature of about 40° C., wash out well with distilled water, and stain to a dark grey or blackish tint in a saturated aqueous hæmatoxylin solution. Decolourise the sections in 0·2 per cent. hydrochloric acid until light yellow, put back into the copper solution until they turn bluish-grey, then wash, dehydrate, clear, and mount in balsam.
Bismarck Brown.—Vesuvine 0·5 Gm., rectified spirit 2, and distilled water 80 C.c.; or a concentrated alcoholic solution may be kept ready for dilution.
Bochmer’s Hæmatoxylin.—Dissolve (a) crystallised hæmatoxylin, 1 Gm., in absolute alcohol, 10 C.c., and (b) alum ammonia, 10 Gm., in distilled water, 200 C.c. Mix the two solutions, and allow to ripen for some days before use. Filter after standing a week. Wash out with aqueous solution of alum (0·5 per cent.) or with acids.
Calberla’s Indulin Stain.—Dilute a concentrated aqueous solution with 6 volumes of water and stain sections for 5 to 20 minutes. Afterwards wash in water or alcohol, and examine in glycerine or clove oil.
Calberla’s Macerating Mixture (for nerve and muscle of embryos).—Dissolve potassium chloride, 0·4 Gm., sodium chloride, 0·3 Gm., sodium phosphate, 0·2 Gm., and calcium chloride, 0·2 Gm., in water, 100 Gm., saturated with carbon dioxide just before using. Mix one volume of this solution with half a volume of Müller’s solution and one volume of water. The Müller’s solution may be replaced by a 2·5 per cent. solution of ammonium chromate. Tissues macerated in this mixture are isolated by teasing and shaking, and mount specimens in concentrated potassium acetate solution.
Canoy’s Salt Solution.—Add a trace of osmic acid to a 0·75 per cent. solution of sodium chloride in water.
Chenzinsky’s Methylene Blue and Eosine.—Mix saturated aqueous solution of methylene blue, 40 parts, with 0·5 per cent. solution of eosine in 70 per cent. alcohol, 20 parts, and distilled water or glycerine, 40 parts.
Cohnheim’s Gold Method.—Place pieces of tissue in 0·5 per cent. gold chloride solution until quite yellow, then expose to light in water acidulated with acetic acid until the gold is thoroughly reduced. Mount specimens in acidulated glycerine.
Crookshank’s Method of Staining Flagella.—Cover-glass preparations are stained with a drop of concentrated alcoholic solution of gentian violet, then rinsed in water, allowed to dry, and mounted in balsam.
Czoker’s Alum Cochineal.—Dissolve alum 1 Gm. in distilled water, 100 C.c., add powdered cochineal, 1 Gm., and boil; evaporate down to half of its original bulk, filter, and add ½ C.c. of liquid carbolic acid.