146 COFFEE 



furrow on the flat side. Strip off small piece of silvery seed-coat. 

 Mount In glycerin or chloral hydrate. 



Diagnosis: — If true coffee-bean, the seed-coat is exceedingly 

 characteristic. See Plate 2, Genus Coffea: Fruit Morphology. 



Preparation of Endosperm: — Soften as for seed-coat examina- 

 tion. Mount thin transverse section of bean In chloral hydrate. 



Diagnosis: — Characteristics of true coffee endosperm. 



( 1 ) Epidermis plus first layer or two In approximation possesses 

 cell-walls of uniform and even diameter. (See Photomicrograph.) 



(2) Remaining endosperm consists of irregularly polygonal 

 parenchymatous cells with exceedingly characteristic, knotty, thick- 

 ened walls — best seen in microtome sections — and very large pits 

 often forming ovate spaces occasionally as long as the width of the 

 cell. These cells contain brilliant, colorless, spherical oil globules, 

 and protein matter. One who Is sufficiently familiar with the 

 various commercial coffee-beans Is able to recognize the seeds of 

 Coffea liberica Bull, which are utilized commercially as fillers, 

 from those of Coffea arahica L., since Arabian coifee-seeds are not 

 only much smaller In size and less coarse in general structure but 

 the entire endosperm is composed of polygonal cells of a fairly 

 uniform size; whereas the endosperm of Liberlan coffee exhibits 

 polygonal cells in the outer portion but toward the center the cells 

 become distinctly oblong and rectangular (see Photomicrograph). 



Preparation of Embryo: — Soften seed as above and dissect out 

 embryo. 



Diagnosis: — True coffee-embryo possesses a thick radicle and 

 two cordate, leaf-like cotyledons. See Plate 2, Genus Coffea: 

 Fruit Morphology. Cotyledons are composed of delicate paren- 

 chymatous cells. 



(b) Ground roasted coffee tissue examination. 



Preparation: — Spread out sample on white paper. 



Diagnosis: — ^Jet black particles are frequently caramel. If so, 

 they will dissolve in water, giving it an intense brown color and 

 bitter taste. 



Preparation: — Sift to separate fine particles (powder). Soften 

 some of the coarser ones. Section any suspicious particles in 

 pith. Decolorize sections by short maceration in solution of 

 chlorinated soda. Examine in dilute glycerin. 



