FOREIGN SUBSTANCES IN COFFEE. 913 
teration of coffees. None of these substances, except sawdust, have 
been detected in the investigations in connection with this report. 
Chemical tests are not applicable. On the detection of a foreign matter, 
which is not among those described, evidently the only course to pursue 
is to prepare slides for microscopic comparisons with others of known 
composition. 
Mogdad coffee.—This adulterant or substitute consists of the seeds of 
the Cassia occidentalis.! E. Geissler? examined Mogdad coffee by Hager’s 
method and found that it sinks very rapidly in water and colors sodium 
chloride solution more intensely than coffee does; its infusion is not 
indifferent to ferric chloride or tannic acid; it contains no starch. 
Janecek * analyzed Mogdad coffee and found a different tannin from that 
in the seed of Coffea Arabica, but no caffeine. 
Mussaenda coffee.—This* substance was supposed to be seeds derived 
from Mussaenda borbonica, but later investigations made at Kew Gar- 
dens show these seeds to be from Gaertnera vaginata. It is stated that 
Mussaenda coffee contains no caffeine. 
Cocoa husks.—Cocoa husks may be identified by the methods given 
under cocoa preparations. 
Sugar and sirup.—Coftees are sometimes treated with sugar or sirup, 
then roasted. When the caramel formed on roasting amounts to an 
appreciable weight, it shoud be considered an adulterant. Stutzer® 
and Reitnair recommend the following method for the examination of 
coffees supposed to have received this treatment: 20 grams of whole 
coffee beans are transferred to a litre flask, covered with 500 ce. water 
and the flask is then violently shaken for five minutes. After shaking 
complete the volume to 1,000 ce., mix and filter off 50 cc. of tLe solution 
into a tarred dish; evaporate to dryness on a water-bath, then transfer 
to an oven heated to 95°-99° and dry two hours; weigh the residue, 
incinerate, and deduct the ash before calculating the organic matter 
extracted. Pure roasted coffee treated by this method gave from 0.44 
to 0.72 per cent organic matter, and colored the water only slightly, 
while coffees which had been roasted with sugar colored the water more 
or less strongly and gave from 1.81 to 8.18 per cent organic extract. 
The glazing of coffees, according to Konig,® is objectionable, not that 
the glazing material is unwholesome, but because coffees so treated 
retain an excess of moisture in the roasting process. The following 
comparative analyses quoted by Konig show the effect of roasting with 
and without sugar. The sirup employed for glazing was simply 
solution of starch sugar. 
1 J. Moeller, Pharm. Centralhalle, 22, 133; Zeitsch. f. anal. Chem., 21, 438. 
2 Op. cit., 22, 134. 
3Chem. Ztg., 1880, 442; Jahresb. d. Chem., 1880, 1070. 
* Pharm. J. Trans., Nov. 16, 1889, 381; Am.J.Pharm., 20, 4, 174. 
5 Zeitsch. f. angew. Chem., 1888, 701, also op. cit., 1890, 706. 
6 Zeitsch. f, angew. Chem., 1888, 631. 
