METHYL GREEN. 67 



CHAPTER IX. 



OTHER ANILIN STAINS. 



104a. For a list showing the colours treated of in this chapter, see 95. 



As regards the direct nuclear stains, the reader is reminded that, as was 

 stated in 95, many if not most of the anilins give a nuclear stain of greater 

 or less purity if they are used in solutions acidified with acetic acid. Under 

 the present heading, only those are mentioned which give in all respects, 

 alike as regards precision and permanence, simplicity of manipulation and 

 other qualities, a really valuable stain. The very existence of methyl green 

 and Bismarck brown is a sufficient reason for being silent, in this connection, 

 with regard to the rest. 



A. Direct Nuclear Stains. 



105. Methyl Green. This is the most common, in commerce, 

 of the " aniliii " greens. It appears to go by the synonyms of 

 Methylanilin green, Vert Lumiere, Lichtgrun, Grrunpulver. 

 When first studied by Calberla, in 1874 (Morphol. Jahrb., iii, 

 1887, p. 625), it went by the name of Vert en cristaux. It is 

 commonly met with in commerce under the name of more costly 

 greens, especially under that of Iodine green. It is important 

 not to confuse it with the latter, nor with Aldehyde green 

 (Vert d'Eusebe), nor with the phenylated rosanilins, Paris 

 green, and Vert d'alcali or Veridine. 



The chief use of methyl green is as a nuclear stain for fresh 

 or recently fixed tissues. For this purpose it should be used in 

 the form of a strong aqueous solution containing a little acetic 

 acid (about 1 per cent, in general) . The solutions must always 

 be acid. You may wash out with water (best acidulated) and 

 mount in some acid aqueous medium containing a little of the 

 methyl green in solution. 



Employed in this way, methyl green is a pure nuclear stain, 

 in the sense of being a precise colour-reagent for nuclein. 

 For in the nucleus it stains nothing but the chromosomes, or 

 nuclein elements : it does not stain either nucleoli of any sort, 

 nor caryoplasm, nor achromatic filaments. Outside the nucleus 



