_Fennel Fruits_, _Fennel Seeds_; F. _Fruits de Fenouil_; G. _Fenchel_.
=Botanical Origin=—_Fœniculum vulgare_ Gärtn. (_Anethum Fœniculum_
L.), an erect, branching plant with an herbaceous stem and perennial
rootstock, growing to the height of 3 or 4 feet, having leaves 3 or 3
times pinnate with narrow linear segments. In allusion to the latter
the plant had also been named _Fœniculum capillaceum_ by Gilibert.
It appears to be truly indigenous to the countries extending from the
Caspian regions (or even China?) to the Mediterranean and the Greek
Peninsula, but is a doubtful native in many parts of Central and
Southern Russia. The plant on the other hand is also found apparently
wild, over a large portion of Western Europe as far as the British
Isles, especially in the vicinity of the sea.
Fennel is largely cultivated in the central parts of Europe, as Saxony,
Franconia and Wurtemberg, also in the South of France about Nîmes, and
in Italy. It is extensively grown in India and China. The Indian plant
is an annual of somewhat low stature.[1176]
The plant varies in stature, foliage, and in the size and form of its
fruits; but all the forms belong apparently to a single species.
=History=—Fennel was used by the ancient Romans, as well for its
aromatic fruits, as for its edible succulent shoots. It was also
employed in Northern Europe at a remote period, as it is constantly
mentioned in the Anglo-Saxon medical receipts, which date as early
at least as the 11th century. The diffusion of the plant in Central
Europe was stimulated by Charlemagne, who enjoined its cultivation on
the imperial farms. Fennel shoots (_turiones fœnuculi_), fennel water,
and fennel seed, as well as anise, are all mentioned in an ancient
record[1177] of Spanish agriculture dating A.D. 961.
=Description=—The fennel fruits of commerce, commonly called _Fennel
Seeds_, are of several kinds and of very different pecuniary value. The
following are the principal sorts:—
1. _Sweet Fennel_,—known also as _Roman Fennel_, is cultivated in the
neighbourhood of Nîmes in the south of France. The plant is a tall
perennial with large umbels of 25 to 30 rays.[1178] As the plants grow
old, the fruits of each succeeding season gradually change in shape
and diminish in size, till at the end of 4 or 5 years they are hardly
to be distinguished from those of the wild fennel growing in the same
district. This curious fact, remarked by Tabernæmontanus (1588), was
experimentally proved by Guibourt.[1179]
[1176] It is an annual even in England, ripening seeds in its first
year, and then dying.
[1177] _Le Calendrier de Cordoue de l’année_, 961, publié par R. Dozy,
Leyde, 1873.
[1178] The Nîmes fennel has been usually referred to _Fœniculum dulce_
DC., but that plant has the stem compressed at the base, and only 6 to
8 rays in the umbel; and is the fennel which is eaten as a vegetable or
as a salad.
[1179] _Hist. des Drogues_, iii. (1869) 233.
The fruits of Sweet Fennel as found in the shops are oblong,
cylindrical, about ⁴/₁₀ of an inch in length by ⅒ in diameter, more or
less arched, terminating with the two-pointed base of the style, and
smooth on the surface. Each pericarp is marked by 5 prominent ridges,
the lateral being thicker than the dorsal. Between the ridges lie
vittæ, and there are two vittæ on the commissural surface,—all filled
with dark oily matter. The fruits seen in bulk have a pale greenish
hue; their odour is aromatic, and they have a pleasant, saccharine,
spicy taste.
2. _German Fennel_, _Saxon Fennel_, produced especially near
Weissenfels in the Prussian province of Saxony; the fruits are ²/₁₀
to ¼ of an inch long, ovoid-oblong, a little compressed laterally,
slightly curved, terminating in a short conical stylopodium; they are
glabrous, of a deep brown, each mericarp marked with 5 conspicuous pale
ridges, of which the lateral are the largest. Seen in bulk, the fruits
have a greenish brown hue; they have an aromatic saccharine taste, with
the peculiar smell of fennel.
3. _Wild or Bitter Fennel_ (_Fenouil amer_), collected in the south of
France, where the plant grows without cultivation. They are smaller
and broader than those of the German Fennel, being from ⅕ to ⅙ of an
inch long by about ¹/₁₅ of an inch wide. They have less prominent
ridges and at maturity are a little scurfy in the furrows and on the
commissure. Their taste is bitterish, spicy, and strongly fennel-like.
The essential oil (_Essence de Fenouil amer_) is distilled from the
entire herb.
4. _Indian Fennel._—A sample in our possession from Bombay resembles
Sweet Fennel, but the fruits are not so long, and are usually straight.
The mother plant of this drug is _F. Panmorium_ DC., now regarded as a
simple variety of _F. vulgare_ Gärtn.
=Microscopic Structure=—The most marked peculiarity of fennel is
exhibited by the vittæ, which are surrounded by a brown tissue. The
latter is made up of cells resembling the usual form of cork-cells. In
Sweet Fennel the vittæ are smaller than in the German fruit; in the
transverse section of the latter, the largest diameter of these ducts
is about 200 mkm.
=Chemical Composition=—The most important constituent of fennel fruits
is the volatile oil, which is afforded both by the Sweet and the German
fennel to the extent of about 3½ per cent.
Oil of fennel, from whatever variety of the drug obtained, consists of
_Anethol_ (or Anise-camphor)
{OCH₃
C₆H₄ { ,
{CH·CH·CH₃
and variable but less considerable proportions of an oil, isomeric with
oil of turpentine. Anethol is obtainable from fennel in two forms, the
solid and the liquid; crystals of the former are deposited when the
oil is subjected to a somewhat low temperature; the liquid anethol may
be got by collecting the portion of the crude oil passing over at 225°
C. The crystals of anethol fuse between 16 and 20°; the liquid form of
anethol remains fluid even at -10° C. By long keeping, the crystals
slowly become liquid and lose their power of reassuming a crystalline
form.
Three varieties of oil of fennel are found in commerce, namely the oils
of _Sweet Fennel_ and _Bitter Fennel_ offered by the drug-houses of
the south of France; their money value is as 3 to 1, the oil of sweet
fennel, which has a decidedly _sweet_ taste, being by far the most
esteemed. The third variety is obtained from Saxon fennel, especially
by the manufacturers of Dresden and Leipzig.[1180] We have been
supplied with type-specimens of the first two oils by the distillers,
Messrs. J. Sagnier, fils, & Cie., Nîmes; a specimen of the third has
been distilled in the laboratory of one of ourselves.
Oil of fennel differs from that of anise by displaying a considerable
rotatory power. We found the above-mentioned specimens, examined in a
column 50 mm. long, to deviate the ray of polarized light to the right
thus:—
Oil of Sweet Fennel 29°·8
” Bitter ” 4°·8
” German ” 9°·1
The rotatory power is due to the hydrocarbon contained in the oil; we
ascertain that anethol from oil of anise is devoid of it.
Fennel fruits contain sugar, yet their sweetness or bitterness depends
on the essential oil rather than on the presence of that body. The
albumen of the seed contains fixed oil, which amounts to about 12 per
cent. of the fruit.
=Uses=—Fennel fruits are used in medicine in the form of distilled
water and volatile oil, but to no considerable extent. The chief
consumption is in cattle medicines, and of the oil in the manufacture
of cordials.