54 STAINING CELLULOSE. 



longer to dehydrate, but holds the stain well ; a thin section 

 dehydrates quickly, but also rapidly loses the stain. 



The differentiation with Aniline Blue and Picric Acid is not 

 so sharp as the above, but more delicate gradations are 

 obtained, from blue through green to yellow. 



The general distribution of the lignified tissue is best 

 observed with a low power, say an inch object glass, when 

 the different colours should show distinctly. 



With Carmine and Methyl Green. Sections of stems 

 and roots containing cellulose and lignified tissue are rinsed 

 in Distilled Water ; place them in Methyl Green Solution for 

 3 or 4 minutes ; rinse in Distilled Water ; wash in 90 p. c. 

 Alcohol for 5 or 10 minutes, which to a great extent removes 

 the Green from the cellulose portion, and thus obtains a purer 

 red with the Carmine ; place the sections in Grenacher's Alco- 

 holic Borax Carmine for 15 or 20 minutes; rinse quickly in 

 Distilled Water to remove adhering stain; pass through 

 90 p. c. Alcohol, dehydrate, clear, and mount in Balsam. 



Acid Green is frequently employed in the place of Methyl 

 Green, but if the latter is free from Violet, or nearly so, it is 

 the better of the two. 



With Carmine and Picric Acid. Einse the sections in 

 Distilled Water ; place them in Grenacher's Alcoholic Borax 

 Carmine 15 to 20 minutes ; rinse for a second in Distilled 

 Water; transfer to Picric Acid (Alcoholic) for 5 or 10 minutes; 

 dehydrate in Absolute Alcohol for 3 to 5 minutes, clear in 

 Cedar Oil, and mount in Balsam. 



With Aniline Blue and Picric Acid. Binse the sections 

 in Water; place them in Hoffmann's Blue (p. 56) for 10 

 minutes; transfer to Picric Acid (Alcoholic) for 10 minutes; 

 dehydrate in Absolute Alcohol for 3 or 4 minutes, clear in 

 Cedar Oil, and mount in Balsam. 



