686 PHARMACEUTICAL BOTANY 
vent postmortem filtration of the alkaloids, by placing them in 
this solution for 5 minutes, and the excess of this reagent washed 
out with water. The K,Fe(CN). solution precipitates the 
alkaloids in the cells which can then be colored by adding a 
drop or two of FeCl; solution. Clearing of the sections may then 
be effected with chloral solution. 
RutTuHentuM Rep AnD LEAD ACETATE SOLuTION.—This is an 
excellent reagent for the detection of mucilage, to which it 
imparts a pink color. Add sufficient ruthenium red to a 10 per 
cent. solution of lead acetate until it shows a wine-red color. 
The lead acetate solution should be prepared with distilled 
water and the ruthenium red added to quantities of it as needed, 
as the reagent is unstable. In pharmacognosy, it is especially 
useful in detecting powdered cacao shells in powdered cocoa and 
chocolate, since the cacao shells are the only portions of the 
cacao seed which contain mucilage. 
SAFRANIN.—Several kinds of safranin solutions are in use, 
viz., Alcoholic Safranin, Anilin Safranin and Aqueous Safranin. 
Alcoholic Safranin is prepared by making a saturated solution of 
safranin (alcohol soluble) in 95 per cent. alcohol and then adding 
an equal volume of water. Anilin Safranin is made by mixing 
equal parts of saturated alcoholic solution of safranin with aniline 
water. Aqueous Safranin represents a 1 per cent. solution of 
safranin (water-soluble) in water. Safranin solutions per se 
stain both protoplasmic contents and cell walls red. When 
properly used in contrast staining they stain all suberized walls 
and lignified walls red. 
ScHWEITZER’s REAGENT (Ammoniated Cupric Oxide Test 
Solution).—This is a valuable reagent for dissolving cellulose. 
It is prepared by dissolving 10 Gm. of copper sulfate in 100 cc. 
of distilled water, adding sufficient 20 per cent. solution of sodium 
hydroxide to precipitate the copper hydroxide which is collected 
on a filter and washing the precipitated copper hydroxide free 
from sulfate with cold distilled water. The precipitate, which 
must be kept wet during the entire process is then dissolved in 
the minimum quantity of ammonia water necessary for complete 
solution. 
