62 
METHODS IN PLANT HISTOLOGY 
Acid Green.—Make a solution according to the general formula, 
or simply make a 1 per cent solution in water. This stains cellulose 
walls and achromatic structures, but scarcely affects lignified walls 
or chromosomes. 
Anilin Blue.—Strong alcoholic solutions are best for botanical 
work. Even though the dry stain may be intended for aqueous 
solution, make a 1 per cent solution in 85 or 95 per cent alcohol. 
This stain can be recommended for cellulose walls, achromatic 
structures of mitotic figures, for cilia, and it is particularly valuable 
for algae. Directions for using it with algae are given in chapter viii. 
Orange G.—Make a 1 per cent solution in water, in 95 per cent 
alcohol, or in clove oil. We prefer the solution in clove oil. 
The orange dissolves very slowly if put directly into clove oil. 
It is better to dissolve 3 or 4 grams of orange in 50 c.c. of absolute 
alcohol. In a well-corked bottle in the paraffin oven at 52° C., this 
much orange may go into solution. Then remove the cork and allow 
about half of the alcohol to evaporate. Pour on 200 c.c. or more 
of clove oil and let it stand for several hours. If any of the stain 
has not gone into solution, pour off the clear fluid, which is now ready 
for use, and pour some more clove oil on the residue, allowing the 
residue to go slowly into solution. In staining, we use a small bottle 
of the orange, pouring it on the slide and draining it back into the 
bottle. The absolute alcohol, carried into the clove oil in this way, 
does no damage, except that it dilutes the stain a little. 
Transfer to the aqueous stain from water; to the alcoholic stain 
from 85 per cent alcohol, since the stain is always applied as a second 
or third stain; use the solution in clove oil after the dehydration in 
absolute alcohol. Times are always short and are to be reckoned in 
seconds rather than in minutes. If the solution in clove oil has 
been used, the slide should be transferred to xylol before mounting 
in balsam. 
This is a plasma stain. It is distinctly a general rather than a 
selective stain, but is valuable as a background for other structures 
which have been stained violet or blue or green. It first came into 
prominence as the third member of the triple stain, safranin, gentian- 
violet, orange. 
Gold Orange.—This stain, which many incorrectly suppose to 
be the same as orange G, is much more readily soluble in clove oil 
and stains with much greater rapidity. 
