REAGENTS AND MOUNTING MEDIA. 477 



dissolved in strong alcohol. Alcanna-tincture also stains protoplasm 

 pale rose red, from a quarter to half an hour being needed. It is 

 sometimes used to identify the ground substance of oil-containing 

 seeds. Fats colour deep red ; cuticle and cork both slowly colour 

 red, in varying degrees, in solution of alkanet in 50 per cent, alcohol. 



A him, watery solution. Restores a section which has been " cleared " too 

 completely, 210. Also in 1 per cent, solution to restore overstating, 

 249. 

 10 per cent. Used as a mordant, 111. 



Alum-carmine, Grenacher's. See Carmine. 



Ammonia, strong watery solution. Used often instead of potash for clearing 

 tissues, etc. Also, after the use of nitric acid, to produce the yellow 

 colour in protoplasm, known as the Xanthoproteid reaction. By 

 the same reaction the middle lamella of thick-walled tissue is stained 

 yellow. Ammonia is also of great service in softening dry herbarium 

 material, preparatory to microscopical examination ; and to neutralise 

 acids. See also p. 161. 



Ammonia hcematin. For method of preparation and use, see p. 249. Used 

 for staining the cell-contents of filamentous algae which have been 

 fixed in picric acid. A rather troublesome method, but with often 

 very beautiful results. 



Aniline-blue, dilute watery solution, acting for up to half an hour. Used 

 as a reagent for staining the callus of sieve-plates in sieve tube:?, 

 which it stains more or less permanently. Glycerine dissolves it 

 out from ordinary cell-walls. It also stains protoplasm, often 

 deeply. Eosin is an excellent subsequent stain. 

 (Hoffmann's Blue), dissolved in 50 per cent, alcohol and containing 

 1 per cent, acetic acid, can be used for the same purpose. It like- 

 wise stains protoplasm and not the cell-wall, as the colour can be 

 removed from the latter by washing in water and mounting in 

 glycerine. Alcohol material must be washed with water before 

 staining. See also Methyl-blue (or Methylene-blue). 

 with pitric acid. See Picric aniline-blue. 



Aniline-green (Acetic). Dissolve aniline-green in 1-2 per cent, solution of 

 glacial acetic acid in distilled water until the solution is of a clear 

 blue-green colour. Especially good for fixing and staining the 

 nucleus in its stages of division. The colour is not permanent. 

 See also Methyl-green. 



oil. Used in preparing Ehrlich's aniline water fuchsiu, 273. 

 sulphate or chloride. Test for lignin. In dilute watery, or in alco- 

 holic solution, alcoholic chloride being best. Treat the section first 

 with this, and lignitied walls are stained yellow. If the section is 

 subsequently treated with dilute sulphuric or dilute hydrochloric 

 acid, the colour is deepened. Or a mixture of the solution with T \ its 

 bulk of sulphuric or hydrochloric acid can be kept. 

 water fitchsin (Ehrlich's). See p. 273 for preparation and use. 



