(I N chemical composition the seeds or beans of coffee 

 ^ are "complex, containing as they do variable pro- 

 portions of proximate principles. The appended analysis 

 represents the average constitution of raw coffee, according 

 to M. Payen, and which is accepted as the standard : 



Constituents. Parts. 



Fat, 10 to 13 



Water, 12 



Caffeine, o.S^"^ 



Cellulose, 34 



Legumen and caseine, 10 



Glucose, dextrine and organic acid, .... 15 



Caffeone and aromatic oils, ....'.. .002 



Caffetannate and potassium, 3 to 5 



Viscid essential oil (insoluble in water), . . . .001 



Ash and other mineral matter, 6 



Other nitrogeneous substances, 3 



In addition to the foregoing, Payen also describes 

 some 0.8 per cent, of free Caffeine and very small quan- 

 tities of essential and aromatic oils, amounting to about 

 0.003 P er cent - of the coffee, in addition to other azotized 

 and saline matter. 



In the process of roasting, coffee undergoes certain 

 chemical changes, as before roasting it contains from 5.7 

 to 7.8 per cent, of sugar, which is reduced to i.i, and 



