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. 



TMoydad coffee. This adulterant or substitute consists of the seeds of 

 the Cassia occidentalis. l E. Geissler 2 examined Mogdad coffee by 1 I ager'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 3 analyzed Mogdad coffee and found a different tannin from that 

 in the seed of Coffea Arabiea, but no caffeine. 



JfiitiMtvn.da coffee. This 4 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. Coffees 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 5 

 and Eeitnair 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 cc. water 

 and the flask is then violently shaken for five minutes. After shaking 

 complete the volume to 1,000 cc., mix and filter off 50 cc. of the 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, 6 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 a 

 solution of starch sugar. 



1 J.Moeller, Pharm. Centralhalle, 22, 133; Zeitsck. f. anal. Chein., 21, 438. 



2 Op. cit., 22, 134. 



3 Chem. Ztg., 1880, 442; Jahresb. d. Chein., 1880, 1070. 



4 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. 



e Zcitsch. f, angew. Chem., 1888, 631. 



