392 METHODS IN PLANT HISTOLOGY 



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 1 c.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 

 precipitate forms. Then add an equal amount of ordinary acetic-car- 

 mine. 



Eosin, — 



Eosin 1 g. 



Water, or 70 per cent alcohol 100 c.c. 



General formula for anilins. — 



Make a 3 per cent solution of anihn oil in distilled water; shake well 

 and frequently for a day; add enough alcohol to make the whole mix- 

 ture 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 Grlibler's cyanin, 

 but gives satisfactory results with an immensely cheaper cyanin, sold 

 by H. A. Metz and Company, 122 Hudson Street, New York. 



Anilin blue. — 



Anilin blue 1 g- 



85 or 90 per cent alcohol 100 c.c. 



For staining before mounting in Venetian turpentine, this stain 

 should be made up in strong alcohol, even if the dry stain is intended 

 for aqueous solution. 



