243 
ARM. - 
those of the snake-root species, and have been 
used, in various parts of Europe, for indigestion, 
fistula, sarcoma. and other diseases. The roots 
of the small species, which grow on dry stony 
grounds in Provence and Languedoc, have been 
used for the same disorders as the common spe- 
cies, and for obstructed perspiration and diseases 
of the lungs. The roots and other parts of the 
long, the round, the bracteated, and the Indian 
species, are used for various medicinal and 
economical purposes by the natives of the Hast 
Indies. Several of the species are very highly 
ornamental, and have long been in great fa- 
vour with amateur gardeners. The three-lobed 
species, tilla few years ago, was always treated 
in Great Britain as a stove plant ; but it has re- 
cently become so far acclimated as to grow in 
favourable situations upon an open south wall; 
and it is there found to be exquisitely ornate, in 
at once its flowers, its large, dark, glossy foliage, 
the long tail-like appendages of its leaves, and 
the convolutions and pendencies of its peculiar 
mode of growth.—Miller’s Gardener's Dictionary. 
—Loudon’s Encye. of Plants—Duncan’s Dispen- 
satory.—Loudon’s Gardener's Magazine—Ainslie’s 
Materia Medica of Hindostan. 
ARM. The upper division of the foreleg of a 
horse. It extends from the lower bone of the 
shoulder to the knee, and, though strictly one 
bone in an old horse, consists of two bones in 
| a young horse. The front and larger bone of 
the arm is nearly straight, and technically bears 
the name of radius, the hinder and shorter bone 
has a comparatively long and powerful projection, 
and technically bears the name of ulna, and 
these are connected by cartilage and ligament, 
which eventually become ossified so as to render 
the two bones one. Good judges of horses, though 
differing in opinion as to various points about 
the arm, are agreed that this important member 
of the animal cught to be large and muscular,— 
that every thoroughbred horse has a full and 
swelling arm,—and that a horse whose arm is 
narrow in front, flat on the side, and deficient in 
play and power of muscle, can neither raise his 
knee for rapid action, nor throw his legs suffi- 
ciently forward for the purposes of either grace- 
fulness, agility, or strength. 
ARMATURE. The parts of vegetable organ- 
ization which seem to have been designed for de- 
fence against the attacks of animals. The most 
frequent and distinguished elements of armature 
are thorns, prickles, spines, and stings. 
ARMENIACA. See Apricot, 
ARMERIA. See Turirt. 
ARNATTO. See Annarro. 
ARNICA. A genus of hardy, perennial, her- 
baceous plants, of the composite family. Five 
species are cultivated as ornamental plants in 
the gardens of Great Britain; one of these five 
is in extensive use and high fame as a medicinal 
| plant; and about thirty other species are known 
_to botanists. Three of the introduced species 
AROMA. , | 
are natives of Austria, grow to the height of e- 
spectively 6, 12, and 18 inches, and bloom in July 
and August,—one of these producing a white 
flower, and the other two yellow flowers. An- 
other of the introduced species, Arnica glacialis, 
is a native of Switzerland, grows about a feot 
high, and produces a yellow flower from June till 
August. The fifth of our species, the chief and 
medicinal one, Arnzca montana, is a native of the 
Alps, the German mountains, and other cold parts 
of Hurope, grows to the height of about a foot, 
and produces yellow flowers in July and August. || 
The powder of it provokes sneezing in the same 
manner as tobacco snuff; and, on that account, 
it is called tabac in the Vosges. The whole plant, 
when used medicinally, is diuretic, antiseptic, 
and strengthening, and removes sensations of 
soreness, stiffness, and pain, occasioned by blows 
and bruises; and the powdered root is applied 
externally in cases of gangrene and bad ulcers; 
and used internally in cases of dysentery, diarrhoea, 
quartan fever, asthenia, rheumatism, bruises, 
gutta serena, and paralysis of the bladder. The 
comminuted preparation of Arnica montana makes 
a prominent figure in homeopathy. 
AROIDEA. A large natural order of plants, 
allied to the sedges and the grasses. It comprises 
the genera pothos, acorus, orontium, tacca, arum, 
caladium, dracontium, calla, Roxburghia, aspidis- 
tra, and tupistra, constituting the tribe Genuine; 
the genera typha and sparganium, constituting 
the tribe Typhineze ; the genus lemna, consti- 
tuting the tribe Pistiaceze; and the genera lep- 
tanthus, aponogeton, Scheuchzeria, potamogeton, 
and triglochin, constituting the genus Junca- 
ginee. The plants of this extensive division are 
on the frontiers of the endogenous portion of the 
vegetable kingdom, and, in structure and char- 
acter, approach very nearly to exogens; they 
present a medium appearance between sedges or | 
grasses, and fleshy or succulent herbs; and they. 
have broad fleshy leaves, and are stemless, her- 
baceous, and coalescent. The Typhines or bul- | 
rushes closely resemble the sedges in habit; the 
pistiaceze are floating plants, with flowers of the | 
most rudimental character; the Juncaginez are 
obscure marsh or river plants ; but the Genuineze, 
or main and proper body of the Aroidese, are pro- 
minent, bold, fleshy plants, and often climb, by | 
their rooting stems, to the tops of lofty trees. 
Some are natives of Europe, but most inhabit the 
tropics. Their thick fleshy roots, when fresh, 
contain an acrid stimulating principle ; but, when 
cooked or otherwise much heated, they lose that 
principle, and, in various instances, become com- 
men articles of food. The flowers of many are 
highly fetid; the leaves and roots of several are 
variously medicinal ; and the entire plants of 
some, particularly in the genera calla, arum, and 
Roxburghia, are cultivated for ornament. 
ARO’MA. The odorous part of plants. An 
emanation, frequently imponderable, from bodies 
which acts on the organ of smell, and-varies with 
