126 
COFFEE 
ONSIDERING the fact that the necessities of our 
daily life, whether as clothing, food, or medicine, 
are mostly provided by the vegetable kingdom, it is 
remarkable how little is generally known of the sources 
from whence we derive our most common articles of com- 
merce. We propose in this article to say something about 
our Coffee, and especially about the mode of detecting 
whether the commercial article is pure or adulterated. 
Although the specific name of the coffee plant, Coffea 
Arabica, appears to indicate the coffee tree to belong 
originally to Arabia, it is with good reason supposed to 
be a native of the mountainous part of the south-west 
point of Abyssinia, having been intreduced from thence 
into Arabia, where it is said to have been first used about 
1450. For about 200 years after this date the whole of the 
coffee used was grown on Arabian soil, from whence the 
Dutch introduced the plant into Batavia, after which it 
was carried into other eastern countries as well as into 
various parts of the western hemisphere. The intro- 
duction of coffee into Europe took place about the middle 
of the sixteenth century, fourteen years before the intro- 
duction of tea. 
Fia. 1.—Branch of Coffee Plant. 
The fruits of the coffee tree when ripe are gathered 
and taken to the pulping house, and placed in a machine 
called a pulper, by which the fleshy covering is removed, 
the beans or seeds pass into a cistern, and the pulps are 
carried off in another direction and are collected and 
preserved for manure ; the seeds themselves are left to 
steep for several hours, so as to soak off any remaining 
mucilage or pulpy matter; they are then washed and 
dried, the parchment and the thin inner skin being re- 
moved by winnowing, after which they are packed in bags 
and ready for shipping. 
The berries or seeds of true Mocha coffee, which is, 
however, now scarcely to be obtained in Europe, are 
usually more round than those of other varieties ; they 
nevertheless vary much in form as well as in size and 
colour; and though the several commercial sorts are 
easily known to a practised eye, they are difficult to detect 
by an ordinary observer. The value to the consumer does 
not in all cases depend so much upon the size or shape of 
the seed as upon its flavour and the strength of its aroma, 
but these qualities cannot be discovered until after roast- 
ing ; therefore in purchasing unroasted coffee, an important 
NATURE 
[Fune 16, 1870 
point is to see that the seeds are not damaged by sea water 
ormouldiness. In roasted “ whole” coffee, the case is dif- 
ferent, for a greater or lesser aroma of more or less fra- 
grance can be detected, the volatile oil, and the peculiar 
astringent acid to which the aroma and flavour are due, 
and which before were latent in the seed, being developed 
Fic. 2.—Coffee Berry (uaz. size). Fic. 3.—Section of Coffee Berry 
(magnified ). P 
by the heat. In the process of roasting, the seeds lose 
about one-fifth in weight, but increase in bulk by about 
one-half. 
The peculiar principle of coffee is called caffeine, and 
is identical with that of tea; it acts as a stimulant upon 
the brain, preventing sleep or drowsiness, and causing 
greater mental as well as bodily activity ; it is also said 
by some chemists to repair or prevent in a remarkable 
degree the too rapid waste of the tissues, so that life can 
be sustained on a smaller quantity of food than would be 
the case without the use of coffee, 
Understanding these principles which Nature has given 
to coffee, and which Science has revealed for our benefit, 
we cannot fail to see the great importance of obtaining 
the article in its genuine state. Upon microscopical 
examination, genuine coffee can be easily detected, the 
cells of the coffee-seed being very irregular in form, and 
having very thick walls with ragged sides. Some of these 
ragged projections belong to the true cell wall, while a few 
are composed of starch granules. Genuine coffee, then, 
should always present this appearance, for there are no 
tubes or spiral vessels in the true coffee seed as there 
are in the root of the chicory; and moreover, in the 
cellular part of the chicory root, the cells themselves 
are larger, the walls are shown as mere fine lines, 
closely fitting together by the pressure exerted upon them 
in the process of growth. This difference will be more 
readily understood by reference to Figs. 4 and 6. In the 
most genuine coffee, however, a certain portion of the skin 
must be present, the microscopical appearance of which 
is shown at Fig. 5 ; by reference also to Fig. 3, it will be 
Fic 4.—Tissue of Coffee Seed, after Fic. 5.—Microscopical appearance 
being roasted and boiled. of Coffee Skin, after being roasted 
and boiled. 
seen how a portion of this skin is naturally enclosed in 
the folds of the seed, so that, while in the process of clean- 
ing it is entirely removed from the surface of the seed, 
the enveloped portion remains, as it cannot be removed 
without breaking or injuring the seed. This, however, 
has been done in the trade, anda series of coffees was 
