FORMULAS FOR REAGENTS 
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Piero-Carmine.— 
Picro-carmine (picro-carminate of ammonia). 1 g. 
Water. 100 c.c. 
Myer’s Carmalum.— 
Carminic acid. 1 g. 
Alum. 10 g. 
Distilled water. 200 c.c. 
Dissolve with heat; decant or filter, and add a crystal of thymol 
to avoid mold. 
This is the stain recommended for Volvox. 
Carmalum (Alum Lake).— 
Carmalum. 1 g- 
Water. 100 c.c. 
Ammonia. lc.c. 
Filter, if there is any precipitate. 
Aceto-Carmine.— 
Heat a 45 per cent aqueous solution of glacial acetic acid to the boiling- 
point, with an excess of powdered carmine. Cool and filter. 
Iron Aceto-Carmine.— 
Add a trace of ferric hydrate, dissolve 45 per cent acetic acid, to a 
quantity of acetic carmine until the liquid becomes bluish red, but no precipi¬ 
tate forms. Then add an equal amount of ordinary acetic-carmine. 
Eosin.— 
Eosin. 
Water, or 70 per cent alcohol. 100 c.c. 
General Formula for Anilins. —Make a 3 per cent solution of 
anilin oil in distilled water; shake well and frequently for a day; 
add enough alcohol to make the whole mixture about 20 per cent 
alcohol; add 1 g. of cyanin, erythrosin, safranin, gentian-violet, etc., 
to each 100 c.c. of this solution. 
Cyanin— This general formula is not at all successful with 
Gruber’s cyanin, but gives satisfactory results with an immensely 
cheaper cyanin, sold by H. A. Metz & Company, 122 Hudson Street, 
New York. 
