62 Methods in Plant Histology 



If the cyanin washes out, stain for 1 hour, and if it still washes out, 

 omit the rinsing in alcohol 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, "cyanophi- 

 lous' ! and "erythrophilous." 



Magdala Red and Anilin Blue. Make both solutions as directed 

 in chap, viii on "The Venetian Turpentine Method." 



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 ex- 

 tracted. 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. 



Acid Fuchsin and Iodine Green Mixtures.- -Two solutions are 

 kept separate, since they do not retain their efficiency long after 

 they are mixed: 



I Fuchsin acid . 1 g. 



L \ Distilled water 50. c.c. 



{ Iodine green . 1 g. 



Distilled water. . 50.0 c.c. 



f Absolute alcohol 100.0 c.c. 



C j Glacial acetic acid 1.0 c.c. 



v Iodine . 1 g. 



