. STAINS AND STAINING 69 



small organisms dried down on the slide, her formula is preferable. 

 Transfer to the alcoholic cyanin from 50 per cent alcohol, stain 5-10 

 minutes or longer; rinse cjuickly in 50 per cent alcohol, transfer to eryth- 

 rosin, 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." 



Phloxine and anilin blue. — In the fourth edition, this combination 

 was described under the heading, Magdala red and anilin blue, but the 

 occasional lots of the red stain which gave satisfactory results were 

 probably phloxine. Make both solutions as directed in chapter viii on 

 "The Venetian Turpentine Method." 



For paraffin sections, stain 3-24 hours in phloxine, dip in 95 per cent 

 alcohol to rinse off the stain, and then stain 2-10 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 phloxine put a pinch of sodium carbonate into the 95 per cent alco- 

 hol. The red may brighten. If the red is too weak, return to the 

 phloxine and try again. From the 95 per cent alcohol transfer to abso- 

 lute alcohol, to xylol, and then mount in balsam. 



