98 G 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[June 10,1871. 
as other than naturalized, but Babington says it is 
truly a native. It is the female plant that is so 
much employed as a brewing ingredient, the strobiles 
being the part used. These are composed of scales, 
each of which has at its base two minute seeds. On 
the scales and seeds are found yellow, granular, 
resinous glands, which, as the strobile ripens, become 
loose and drop off. These minute bodies are used in 
pharmacy under the name of lupulin, and in them 
resides the flavour so highly prized. The strobiles 
yield from 8 to 18 per cent, of these lupulinic grains. 
They are most interesting microscopic objects, from 
vt)o to lio °f an inch i 11 diameter, and are shaped 
like flattened, subovate little saucers, and covered 
over with cell markings. They are attached by a 
short pedicel. As they get older, the central portion 
expands, and instead of the former concave sfliape, 
swell out and become convex. 
According to the analyses of MM. Pelletier and 
Payen, the so-called lupulin consists of volatile oil, 
2 per cent.: bitter extract, 10 per cent.; resin, 50 
per cent.; and tannic acid, 5 per cent.,—the re¬ 
mainder being gum, calcium and potassium malates, 
otc. When distilled with water, about 1 per cent, of 
valerianic acid (C 5 H 10 O 2 ) passes over, with an oil 
■consisting of a hydrocarbon (C 10 H 16 ) and valerol 
(C g H 10 O). The latter, by keeping, becomes con¬ 
verted into valerianic acid. Hence the peculiar 
cheesy flavour of old hops. 
C 6 H 10 O + H.O = C S H 10 0 2 + 2H. 
Valerol, Valerianic 
acid. 
One hundredweight of hops will yield about forty 
pounds of extract as ordered by the Pharmacopoeia. 
Nat. Ord. Ulmace.e. 
The plants forming this Order differ from the last 
by never having the flowers in the form of catldns, 
but in clusters of flat, membranous, leaf-like expan¬ 
sions, with a notch at the top, and one seed fixed in 
the centre. 
Ulmiis campestris (Linn.). 
This noble tree occurs very generally throughout 
the neighbourhood. Fine examples may be exa¬ 
mined in the grove leading to Bedland Court, and in 
some of the city squares. The finest specimens are 
found where the soil is rich, friable and sandy. 
Elm bark is a tonic and astringent, and is much 
prized in Norway for tanning leather used for glove- 
maldng. Ulmin, so familiar to the agricultural stu¬ 
dent as one of the constituents of mould, peat, etc., 
derives its name from the substance found in the 
black excrescences so often observed on the trunks 
of old elms. 
Elm bark contains about 20 per cent, of a kind of 
mucilaginous substance, 3 of tannin, G of resin and 
10 of inorganic salts. 
Nat. Ord. AmentacejE. 
Tfiis valuable Order of trees is distinguished by 
the flowers being arranged in catldns (amenta). 
Only one is mentioned in the Pharmacopoeia. 
Quercus pedunculata (Willd.). 
Perhaps no natural object lias been so frequently 
mentioned by writers of every age and clime as the 
Oak. It is frequently mentioned in the Bible, 
although probably in many passages the evergreen 
oak (Q, Ilex) is the species meant. It was held 
sacred by the Greeks, Homans, Gauls and Britons. 
Horace speaks of 
“ Quercus et ilex 
Multa frugc pecus, mulla dominum juvet umbra.” 
and in many of his beautiful descriptions of rural 
scenes alludes to the groves of oak-trees:— 
“ Querceta Gargani laborant.” 
In his ‘ Bucolics,’ ‘ Georgies ’ and ‘ iEneid,’ Virgil 
over and over again mentions the monarch of the 
forest as one of the principal objects of a sylvan 
landscape:— 
“ Tbe monarch oak, the patriarch of the trees, 
Shoots rising up, and spreads by slow degrees; 
Three centuries he grows, and three he stays 
Supreme in state, and in three more decays.” 
The chief value of the plant resides in the bark, 
which is celebrated for the large quantity of tannic 
acid it contains. The barks are gathered in the 
spring, because they contain a larger percentage 
and are more easily separated from the wood. The 
bark of young stems is most highly prized. Besides 
tannic acid, oak-bark contains gallic and quercitannic 
acids, and about 2 per cent, of ash. 
The following example of the percentage of tannic 
acid from oak-barks, at different periods of the year, 
are taken from the author’s laboratory journal:— 
Entire bark in May = 6'05 per cent. 
„ August = 4*39 ,, 
Inner bark only May = 21*13 „ 
„ August = 15*31 ,, 
Tannic acid (C 27 H„ 2 0 17 ) from oak is that kind 
which gives a bluisli-biack colour with ferric salts. 
It is glucoside, for when boiled with diluted acid it 
becomes converted into glucose and gallic acid 
(C 7 H 6 0 5 ). 
C 27 H 22 0 17 + 4H 2 0 = C 6 H 12 0 6 + 3 C 7 H 6 0 5 . 
Tannic acid. Glucose. Gallic acid. 
Gallic acid differs from tannic by producing no 
precipitate with gelatine. It is, however, a singular 
circumstance that when mixed with gum it has that 
property. 
When tannic acid is heated, it becomes decom¬ 
posed into pyrogallic acid (C c H 6 0 3 ), so well known 
as an article of great use in photography, and a sin¬ 
gular dark-coloured insoluble substance termed me¬ 
tagallic acid (C 6 H 4 0 2 ). 
= 3C g H g 0 3 -f- C 6 H 4 0 2 -f- 3 C0 2 . 
Tannin. Pyrogallic Metagallic 
acid. acid. 
The tannic acid procured from catechu, cinchona, 
etc. differs from that contained in oak-bark, by giv¬ 
ing, with ferric salts, a greenish instead of a bluish- 
black precipitate, and by not yielding glucose or 
pyrogallic acid. Quercitannic acid present in oak- 
bark differs from the usual tannic acid of the galls 
by being non-convertible into gallic acid or pyro¬ 
gallic acid, and from the tannic acid of catechu by 
giving a bluisli-biack precipitate with ferric salts. 
During the last few years the oaks in the West of 
England have been infested by galls. A great 
number have been analysed by the author, but have 
proved useless for commercial purposes, from the 
small percentage of tannic acid present. This may 
be owing to being allowed to remain on the tree till 
the insect escapes, for nearly all were perforated. 
