66 
METHODS IN PLANT HISTOLOGY 
may be used. Miss Thomas recommends 1 gram dissolved in 100 
c.c. of 95 per cent alcohol. After the solution is complete, add 
100 c.c. of distilled water. Since the combination is used only for 
paraffin sections or for small organisms dried down on the slide, her 
formula is preferable. Transfer to the alcoholic cyanin from 50 per 
cent alcohol, stain 5 to 10 minutes or longer; rinse quickly in 50 
per cent alcohol, transfer to erythrosin and stain 30 seconds to one 
minute. Rinse quickly in 50 per cent alcohol, then in 95 per cent and 
absolute alcohol. Clear in xylol and mount in balsam. 
If aqueous stains are used, transfer to the cyanin from water, 
rinse in water, stain in erythrosin, rinse in water, and transfer directly 
to 95 per cent alcohol. If the cyanin washes out, stain for 1 hour, 
and if it still washes out, omit the rinsing and transfer directly from 
the cyanin to the erythrosin. 
The erythrosin may be used first; in this case stain for 5 minutes 
in erythrosin, transfer directly to cyanin, and stain for about 10 
seconds. Dehydrate in 95 per cent and in absolute alcohol, clear 
in xylol or in clove oil, and mount in balsam. 
The stains wash out so rapidly that the series of alcohols cannot 
be used. 
Chromosomes and nucleoli stain blue and achromatic structures 
red. Lignified structures stain blue and cellulose walls red. The 
various cell constituents are often sharply differentiated. It was this 
combination which suggested the now obsolete terms, “cyanophilous” 
and “erythrophilous.” 
Magdala Red and Anilin Blue.—Make both solutions as directed 
in chapter viii on “The Venetian Turpentine Method.” 
For paraffin sections, stain 3 to 24 hours in Magdala red, dip in 
95 per cent alcohol to rinse off the stain, and then stain 2 to 10 minutes 
in the anilin blue. Dip in 95 per cent alcohol to rinse off the stain, 
and treat for a few seconds with alcohol slightly acidulated with 
hydrochloric acid (one drop to 50 c.c. of 95 per cent alcohol). In the 
acid alcohol the blue will become more intense, but the red would 
soon be extracted. Wash in 95 per cent alcohol to remove the acid. 
If the acid has weakened the Magdala red, put a pinch of sodium 
carbonate into the 95 per cent alcohol. The red may brighten. If 
the red is too weak, return to the Magdala red and try again. From 
the 95 per cent alcohol, transfer to absolute alcohol, to xylol, and then 
mount in balsam. 
