910 FOODS AND FOOD ADULTERANTS. 
amined for in the ash by the usual qualitative methods for the de- 
tection of lead and chromium. The ash should also be examined for 
copper, and in the case of moist preparations of coffee preserved in tin 
eans, both tin and copper should be searched for. Azo-colors are de- 
tected as follows: 
Azo-colors are detected by treating the beans with strong alcohol, evaporating the 
solution to dryness, and treating the residue with water. This solution will give 
the characteristic reactions of these dyes. 
It is preferable, when possible, to detach the facing by shaking the 
coffee with cold water. The sediment may be examined chemically or 
microscopically. Lead, tin, copper, and arsenic are the only objection- 
able metals lable to be present in coffee or its preparations. The ash 
should be examined for these metals. 
Chicory.—One of the common adulterants of coffee is the prepared 
root of the chicory plant, Cychoriwm intybus. There are several chem- 
ical methods for the detection of chicory, depending upon positive and 
negative tests. Ground chicory when thrown on cold water sinks 
quickly, coloring the water, and is soon softened, whereas ground 
roasted coffee floats, imparting no color. Chicory is easily bleached by 
chlorinated soda (labarraque solution); coffee is but slowly affected by 
this bleaching agent. The coloring! matter of chicory is not precipi- 
tated by iron salts, while that of coffee is colored green and is partially 
precipitated. G. C. Wittstein? employs the following method: 
Boil 30 drops of the coffee infusion in a test tube with 2 drops of con- 
centrated hydrochloric acid; add 15 drops potassium ferrocyanide solu- 
tion (1 part of the salt to 8 of water), and again boil until the liquid 
becomes a dark green; add 6 drops of potassium hydroxide solution and 
boil; if chicory is present the liquid will become brown and murky, 
otherwise a precipitate will separate and settle to the bottom of the 
tube, leaving the supernatant solution of a light-yellow color. 
A. Franz? states that copper acetate gives a greenish-brown precipi- 
tate with coffee infusions and adark-red brown precipitate with chicory. 
With coffee the supernatant liquid is greenish and with chicory red 
brown. 
Hiepe‘ tests for chicory as follows: Ignite 25 grams of the sample 
and determine the amount of chlorine present in the ash. Coffee con- 
tains 0.03 per cent chlorine, and chicory as high as 0.28 per cent. Kor- 
nauth® gives the maximum and minimum chlorine content of coffee as 
respectively 0.06 per cent and 0.15 per cent. 
Chicory can be most readily and certainly identified in mixtures by 
means of the microscope. The microscopic appearances of coffee and 
chicory are Shown in Plates XLII, XLIII, and XLv. 
' Ding. Polyt. Journ., 211,78; Jahresb. d. Chem., 1874, 1043. 
2 Ding. Polyt. Journ., 215, 834; Am. Chemist, 6, 220. 
3 Arch. Pharm. [3], 8, 298; Jahresb. d. Chem., 1876, 1021. 
4Moniteur Scientific [3], 10, 1339; Jahresb. d. Chem., 1880, 1220. 
5 Mitt. a.d. Pharm. Inst. u, Lab. f. Angew. Chem. Erlangen, Heft 3, 1 to 56, 
