Squire (Canada Balsam).—Dry the balsam over a water bath until brittle when cooled, then to each 200 Gm. add 100 C.c. of benzole or rather less xylol.
Squire (Dammar Solution).—(1) Dissolve 100 Gm. of dammar in 100 C.c. of benzole. (2) Dissolve 100 Gm. of dammar in 200 C.c. of turpentine oil, and add 50 Gm. of mastic dissolved in 200 C.c. of chloroform.
Squire (Potassium Acetate Solution).—Dissolve 250 Gm. of potassium acetate in 100 C.c. of water, by the aid of gentle heat, and filter. This is used as a mounting medium.
Squire (Treatment of Sections).—Imbed tissues to be cut in paraffin melting between 45° and 50° C., according to the temperature of the room and the nature of the material. Afterwards preserve the sections, prior to staining and mounting, in 50 per cent. alcohol, or in a mixture of equal volumes of glycerine and thymol water (1 in 1500). Sections may be conveniently washed in alcohol, dehydrated, and cleared, in small wide-mouthed bottles.
Topping’s Solution.—-Mix 1 part of absolute alcohol with 5 parts of water, or 4 parts of water and 1 part of aluminium acetate. Add an equal volume of glycerine before use.
STAINS AND STAINING METHODS.
Apáthy’s Hæmatoxylin Stain.—After staining in 1 per cent. solution of hæmatoxylin in 70 or 80 per cent. alcohol, wash out in 1 per cent. solution of potassium bichromate in alcohol of the same strength. The bichromate solution should be freshly made by mixing 1 part of a 5 per cent. aqueous solution with about 4 parts of 80 to 90 per cent. alcohol.
Alferow (Silver Staining).—An acid solution of silver picrate, lactate, acetate, or citrate, is prepared by adding to 800 C.c. of the solution 10 to 15 drops of a concentrated solution of the acid of the salt taken.
Bethe’s Stain for Chitin.—Place series of mounted sections on slides in a freshly prepared 10 per cent. solution of aniline hydrochloride, containing 1 drop of hydrochloric acid for each 10 C.c., for 3 or 4 minutes, then rinse in water, and put the slide with sections downwards in a 10 per cent. solution of potassium bichromate. The process may be repeated if the stain is not sufficiently intense, but the sections must be well rinsed with water after each immersion.
Beale’s Ammonia Carmine.—Carmine, 10 grs.; strong solution of ammonia, 30 mins.; distilled water, 2 ozs.; alcohol, 0·5 oz.; glycerine, 2 ozs. Dissolve the carmine in the ammonia by the aid of heat, boil for a few seconds, and let the solution cool. Then allow the excess of ammonia to evaporate, add the other ingredients, and filter. If any carmine should deposit on keeping add one or two drops of ammonia solution to redissolve it.