APPENDIX. 391 



Ammonia may be used (1) as a clearing agent instead of potash, 

 its action being less vigorous ; (2) in the xanthoproteic test for 

 proteins, which give a yellow colour with ammonia, deepening to 

 orange on adding nitric acid. 



Ammonium Molybdate, as concentrated solution in a saturated 

 solution of ammonium chloride, gives a yellow precipitate in tissue 

 containing tannins. 



Aniline Blue, generally used in alcoholic solution, is a good 

 general stain, and is especially good for Algae and for nuclear 

 structure and mitotic figures. It makes a good stain for cellulose 

 walls when used along with safranin, which remains in the lignified 

 walls, thus giving an effective double staining. 



Aniline Oil may be used to dehydrate specimens to be mounted 

 in balsam, since it will absorb about 4 per cent, of water, and may 

 be kept dehydrated by placing in it a piece of solid potash, which 

 is insoluble in the aniline oil. After treatment with aniline oil, the 

 sections may be at once mounted in balsam. 



Aniline Sulphate makes lignified walls yellow, leaving the 

 other tissues unstained. Make a saturated solution in water, filter, 

 and add a few drops of sulphuric acid till the solution is distinctly 

 acid in reaction. If aniline chloride is used, add hydrochloric 

 instead of sulphuric acid to the solution. 



Asparagin. Saturated solution in water is used as a test for 

 asparagin precipitated in tissues by the action of alcohol ; if the 

 crystals consist of asparagin they will be unaffected, while crystals 

 of other soluble substances would be dissolved by the asparagin 

 solution. 



Barfoed's Solution. To 200 c.c. of 5 per cent, solution of 

 neutral acetate of copper add 5 c.c. of 40 per cent, acetic acid. 

 When this solution is heated with glucose, red copper oxide is 

 precipitated ; no reaction is given with cane or malt sugar or with 

 dextrin. 



Barium Chloride is used to distinguish calcium oxalate from 

 calcium sulphate. When the reagent is added, calcium oxalate 

 if present is left unchanged, while a fine granular layer of barium 

 sulphate is formed on crystals of calcium sulphate. 



Baryta Water, or aqueous solution of barium hydrate, prepared 

 by adding excess of the barium hydrate to water and filtering, is 

 used in physiological experiments to absorb carbon dioxide, barium 

 carbonate being formed as a white precipitate. 



Boracic Acid is used for mounting sections containing mucila- 

 ginous membranes. The sections are cut from dry material and 

 placed in 10 per cent, solution of neutral lead acetate to harden the 

 gummy layers, then they are stained with methyl blue, washed in 

 water, and mounted in 2 per cent, solution of boracic acid. 



