STAIN TECHNIQUE 49 



When compared with other shades of Methyl Violet on the same 

 kind of plant tissues, the 2B shade is the best of the series. As a 

 counterstain after Acid Fuchsine, C. I. No. 692, Biebrich Scarlet, 

 C I. No. 280, Crocein Scarlet MOO, C. I. No. 252, or Orange II, 

 C. I. No. 151, Methyl Violet B may be used for from five seconds 

 to five minutes depending on the time taken for the first and lighter 

 color. An especially noteworthy triple stain for root, stem, and 

 leaf sections is obtained by using a mixture of two parts Orange II 

 and one part Biebrich Scarlet for 24 hours, and after a rinse in 

 distilled water, a counterstain in Methyl Violet B for two or three 

 minutes. The colors are very fast as well as brilliant. 



681. Crystal Violet, Methyl Violet 10B is a basic dye, light 3. 

 Gentian Violet is either a mixture of two or more shades of Methyl 

 Violet or it is Crystal Violet containing dextrin. Crystal Violet is 

 more selective in its staining of minute cell structures than other 

 basic violet dyes. The dye is dissolved in distilled water with 

 ammonium alum and acetic acid ; it is used in the same manner as 

 and after the same acid dyes given in combinations with Methyl 

 Violet B. 



682. Ethyl Violet is a basic dye, light 5. Tissues are not 

 stained uniformly and the color is very fugitive. 



683. Methyl Violet 6B, Benzyl Violet, Gentian Violet 6B is a 

 basic dye, light 3 ; 1/10 gram in 95 ml. of distilled water, 5 ml. of 5 

 per cent ammonium alum, and ^ ml. of acetic acid. Plant tissues 

 are stained blue-violet similar to the color obtained with Crystal 

 Violet but the differentiation of minute cell structures is not so 

 clear. As a counterstain, Methyl Violet 6B is used for three min- 

 utes after most of the red acid dyes such as Acid Fuchsine, Crocein 

 Scarlet MOO, or Orange II. 



684. Methyl Green is a basic dye, light 4. The Methyl Green 

 now on the market, both the domestic and imported product, is a 

 blue or blue-green dye ; it is unstable and fugitive. The green dye 

 of former manufacture, labeled Methyl Green, was a different dye 

 or a mixture. On various plant tissues the stain is blue-green to 

 blue-violet. Instead of Methyl Green use Methylene Green, C. I. 

 No. 924. 



