APPENDIX II 683 
Alkaline Tartrate Solution.—Dissolve 173 Gm. of crystallized 
potassium and sodium tartrate and 50 Gm. of sodium hydroxide 
in sufficient distilled water to make the solution measure 500 cc. 
Keep in rubber-stoppered bottles. 
Mix exactly equal volumes of the two solutions when required, 
This solution yields a precipitate of cuprous oxide with reducing 
sugars. 
FERRIC CHLORIDE SoLuTIon.—A 1 per cent. solution of ferric 
chloride in distilled water is used to detect the presence of 
tannin. It yields a dark green to bluish-black precipitate with 
tannin. 
Fucustn (Basic).—Dissolve 1 Gm. of fuchsin in 100 cc. of 
95 per cent. alcohol and add an equal volume of water. This 
solution will impart different tints of red to the various tissues. 
It has been found especially useful in staining sections which are 
to be photomicrographed. 
Fucusin, Actb.—A 0.2 per cent. aqueous solution is useful 
in staining plastids and the phytoglobulins of aleurone grains. 
A 1 per cent. solution in 50 per cent. or 70 per cent. alcohol 
is occasionally employed in conjunction with methyl green or 
fast green in the double staining of tissues of plants. 
GentiAN VioteT (METHYL VioLeT).—An aqueous solution, 
made by dissolving sufficient of the dye in 1 per cent. acetic acid 
solution to impart a deep violet color, is useful in fixing and 
staining pollen grains, spores and other fresh plant material. 
A 1 per cent. solution in distilled water is used in conjunction 
with Safranin and Orange G. solutions in staining material used 
for the study of nuclear divisions. 
Griycerin, DituTe.—Equal parts of pure glycerin and dis- 
tilled water. Used as a mounting medium. 
GrycerInE GuM.—Dissolve 20 Gm. of gum arabic and 20 
Gm. of glycerine in 15 cc. of water. Useful for fixing small 
fruits or seeds on pith before sectioning. 
Ha@MaTOXYLIN, DELAFIELD’s.—Used for double-staining, see 
p. 701. ie ‘ : 
H&MATOXYLIN, HEIDENHAIN’S.—This consists of two solutions, 
a mordant and a stain. The mordant (Solution I) is prepared 
