16 THE NORTHERN MICROSCOPIST. 
SNe | see 
MANCHESTER MICROSCOPICAL SOCIETY.—On Thursday, Nov. 
18th, after the formal business of the meeting was finished, Mr. John Boyd 
exhibited some camera lucida drawings of Vaginicola valvata ; the long pos- 
terior-spine Daphnia Schefferi, and also of Chydorus sphericus, all of which he 
had taken in Derwentwater. A letter was read from Mr. Thomas Brittain, 
saying that he had just returned from a sojourn in the Lake district with numer- 
ous specimens, and that he would be happy to place three evenings at the 
disposal of any members of the Society who chose to call upon him. 
Mr. George E. Davis, F.R.M.S., distributed numerous specimens of Chy- 
dorus sphericus, and also made a statement referring to the publication of THE 
NORTHERN MICROSCOPIST. 
The paper for the evening was read by Mr. A. W. Duncan, upon Coffee and 
its adulterations. Mr. Duncan commenced by giving a botanical description of 
the coffee tree (Coffea Arabica) which he stated was of the natural order Cin- 
chonaceze. The tree came to full bearing in three years, and under favourable 
circumstances will continue bearing for twenty years or more. ‘The flowers 
grow close to the stem, and are of a beautiful white colour. The fruit is like 
that of the cherry tree, and contains, when ripe, two seeds surrounded by a 
yellowish pulp. 
After the fruit is plucked (the principal crop in the months from April to July) 
it is partly dried on the plantation in order that it may reach in safety, the 
manufactory where it is prepared for shipment ; but on plantations of the first 
order this operation is generally performed within its precincts. 
In some places the fruit is pulped in ‘order to liberate the seed, which alone 
are useful. Before the seeds can be used they are roasted and ground, and 
great care has to be taken over this operation. 
The usual adulterations of coffee are readily detected as roasting only slightly 
alters its microscopic character. We have first the testa or covering by which 
it is surrounded. ‘This consists of a single layer of elongated adherent cells, 
resting on a thin membrane having an indistinct fibrous structure. The cells 
have oblique markings on their surface. This membrane can be readily 
femoved from roasted coffee, as during the process of roasting it separates from 
the seed. It is known as coffee flights. A few small double spiral vessels are 
usually found in the groove or raphe which runs along each seed. 
The seed proper is entirely made up of small angular cells, very firmly 
adherent, and containing iu their interior deposits of oil. In the act of roasting 
the cells are charred, but their structure and shape are scarcely altered ; the 
deposits of oil, however, are no longer seen in their cells, but are disseminated 
through the entire structure of the seed. Coffee contains no starch. We have, 
therefore, in pure coffee only to look for two structures, the cellular matter and 
the membrane, but the latter may be entirely absent, as it is of no value. 
Coffee was formerly very extensively adulterated : the following are some of 
the substances used,—carrot, parsnip, beet, bean, lupin, dandelion root, chicory, 
mangold-wurzel, acorn, roasted grain (principally wheat), baked horse’s and 
bullock’s livers, venetian-red, earth, sawdust, &c. Of late years adulterations 
other than chicory are almost unknown ; recently, however, date stones have 
been found in some samples. 
The public, especially the poorer classes, have become so used to chicoried 
coffee, which gives a much darker decoction than the genuine article, that when 
they receive the pure coffee fancy there is something wrong, the prevailing 
opinion being that blackness is a test of strength. 
The plant from which chicory is made is the Cichorium Intybus, of the tribe 
Cichoreze, and of the order Composite. It is an indigenous plant with a peren- 
nial root, better known, perhaps, under the appellation of wild succory. The 
greater part is formed of rounded or oblong cells containing granular matter, 
and their appearance is very characteristic. ‘The best seen and most distinctive 
character observed when examining coffee adulterated with chicory are the 
