ADULTERATION OF COFFEE. 117 



intimately mixing the sample, place a small quantity in a test-tube 

 with a few drops of Liquor Potassae ; boil for a few minutes, and 

 when it has cooled, pour off the potash and wash the residue 

 well several times with distilled water. After washing, spread a 

 small portion on a glass slip ; with a needle-point pick out any 

 small hard pieces which might break the cover-glass, and such as 

 you may be pretty certain are pure coffee ; whilst picking these 

 out, observe whether there are any small, soft, jelly-like pieces ; 

 if so, you may be equally certain they are chicory. 



Now cover with thin glass, and examine with a half-in. or 

 quarter-in. objective. 



The Coffee-berry is made up of two distinct parts : — the sub- 

 stance of the berry, and the testa, or membrane, by which it is 

 surrounded. 



The substance of the berry consists of vesicles, or cells, of an 

 angular form, which adhere so firmly together that they break up 

 into pieces rather than separate into distinct and perfect cells. 

 The testa, or investing membrane, presents a very different 

 structure from that of the berry itself, and if once fairly recog- 

 nised cannot be confounded with any of the structures found in 

 chicory, or in the other adulterants of coffee. It is made up prin- 

 cipally of elongated and adherent cells, forming a single layer, and 

 having oblique markings upon their surfaces ; and these cells rest 

 upon another thin membrane, which presents an indistinct and 

 fibrous structure (PI. ii. Fig. 3). In the groove which runs along 

 each berry, a few small vessels, each formed of a single and 

 continuous spiral thread, may usually be found. 



In the Chicory root, four parts or structures may easily be 

 detected, — cells, dotted vessels, vessels of the latex, and wood- 

 fibre (Fig. i). The bulk of the root consists of small cells, 

 generally rounded, but sometimes narrow and elongated. The 

 dotted vessels are particularly abundant in the central and harder 

 parts of the root, which they traverse in bundles ; they are cylin- 

 drical, unbranched tubes, tapering to a point at either extremity, 

 and marked on the surface with short fibres that describe an 

 interrupted, spiral course. 



The vessels of the latex, vasa laticifera, form branched and 

 frequently-anastomosing tubes, of smaller diameter than the dotted 

 vessels, and with smooth membranous walls. The woody fibre of 

 chicory-root does not present any markings or other peculiarities 

 of a special character. 



These, then, are the distinctive differences between Coffee and 

 Chicory ; and if the amateur microscopist will make himself 

 thoroughly conversant with the two substances in their pure state, 

 he will be able to pronounce at any time with certainty, 



