Heidenhain’s Hæmatoxylin Method.—Dissolve (a) hæmatoxylin, 1 Gm., in distilled water, 300 C.c.; (b) potassium chromate, 1 Gm., in distilled water, 200 C.c. Small pieces of tissue hardened in alcohol or picric acid are placed in (a) for 12 to 24 hours, and then transferred for a similar length of time to (b). Wash thoroughly in water, dehydrate in alcohol, and imbed in paraffin.
Henle’s Stain (for nervous tissue).—Sections are left in palladium chloride solution (1:300 to 1:600) till they are of a straw colour, then rinsed in water and stained with strong ammonia carmine.
Henneguy’s Alum Carmine.—Excess of carmine is boiled in saturated solution of potash alum, and 10 per cent. of glacial acetic acid added on cooling. Allow to settle for some days, and then filter.
Henneguy’s Permanganate Method.—Treat sections for 5 minutes with 1 per cent. potassium permanganate solution, then wash in water and stain with safranine, rubin, gentian violet, vesuvine, preference being given to a safranine solution prepared with aniline water.
Hermann’s Platino-aceto-osmic Mixture.—Mix 15 parts of 1 per cent. platinic chloride solution, 1 part of glacial acetic acid, and 2 or 4 parts of 2 per cent. osmic acid.
Hertwig’s Macerating Fluid.—Mix equal parts of 0·05 per cent. osmic acid, and 0·2 per cent. acetic acid. Medusæ are treated with this mixture for 2 or 3 minutes, then washed in 0·1 per cent. acetic acid until free from osmic acid. Leave them for 24 hours in the dilute acetic acid, then wash in water, stain with Beale’s carmine, and mount in glycerine. For Actiniæ use 0·04 per cent. osmic acid and make both solutions with sea water. Wash out with 0·2 per cent. acetic acid, and stain with picro-carmine.
Hessert’s Method for Staining Flagella.—Fix the film by treating cover-glass preparations with a saturated alcoholic solution of mercuric chloride, wash, and stain for 30 or 40 minutes in a hot 10 per cent. aqueous solution of saturated alcoholic solution of fuchsine.
Hoffmann’s Blue Stain.—Dissolve 1 Gm. of Hoffmann’s blue in 20 C.c. of rectified spirit and 80 C.c. of distilled water, then add 0·5 C.c. of glacial acetic acid. As a nuclear stain immerse sections for 10 minutes or more, rinse in water, wash in 90 per cent. alcohol, dehydrate, clear, and mount in balsam. To stain sieve areas, less time is required, 5 to 10 minutes, rinse in distilled water, and mount in glycerine; or dehydrate, clear, and mount in balsam.
Hoyer’s Shellac Injection Mass.—Dissolve shellac in 80 per cent. alcohol to the consistency of a thin syrup, and strain through muslin of medium thickness. Colour with aniline colours in alcoholic solution, or by means of vermilion or other pigment suspended in alcohol.
Hoyer’s Silver Nitrate Gelatine Mass.—Mix a concentrated solution of gelatine with an equal volume of a 4 per cent. silver nitrate solution and warm, then add a very small quantity of aqueous pyrogallic acid solution to reduce the silver salt, and add chloral and glycerine as in the carmine gelatine mass.