quently they afford no certain criterion of 
truth. But, with respect to the conduct of 
life, and the pursuit of happiness, probable 
appearances are a sufficient guide, because 
it is unreasonable not to allow some degree 
of credit to those witnesses who commonly 
give a true report. 
ACADEMY, in Grecian antiquity, a 
large villa in one of the suburbs of Athens, 
where the sect of philosophers called Acade- 
mics held their assemblies. It took its 
name from one Academus, or Ecademus, a 
citizen of Athens ; as our modem academies 
take theirs from it. This term was also 
used metaphorically, to denote the sect of 
Academic Philosophers. See Academics. 
Academy, in a modern sense, signifies a 
society of learned men, established for the im- 
provement of arts or sciences. See Society. 
AC/ENA, in botany, a genus of the Te- 
trandria Monagynia class and order of plants. 
There is but a single species, \Vhich is a 
Mexican plant. 
ACALYPHA, in botany, a genus of 
plants belonging to the Monoecia Monodel- 
phia class, and the natural order of Tricoccas, 
called the Tick-fruit. There are fourteen 
species : the A. virginica, grows naturally in 
Virginia, and in Ceylon : the A. virgata is a 
native of the warmest countries, and grows 
plentifully in Jamaica ; its leaves resemble 
those of the annual nettle, and sting as 
much. Most of the other species are na- 
tives of the West Indies. The plants have 
no beauty to recommend them, and are pre- 
served in some botanic gardens merely on 
account of variety. 
ACANTHA, among botanists, a name 
given to the prickles of thorny plants. 
Acantha is also used by zoologists for 
the spines of certain fishes, as those of the 
echinus marinus, &c. 
ACANTHACEOUS, among botanists, 
an epithet given to all the plants of the thistle 
kind, on account of the prickles with which 
they are beset, 
ACANTHONOTUS, in natural history, 
a genus of fishes of the order Abdominales : 
the generic character is, body elongated, 
without dorsal fin: spines several, on the 
back and abdomen. ’■ There is but one 
species, the nasus, about §0 inches long, a 
native of the East Indies. The eyes are 
large, and the nostrils conspicuous : the body, 
which is of a moderate width for about the 
third of its length, gradually decreases or 
tapers towards the extremity: both head 
and body are covered with small scales, and 
are of a bluish tinge, with a silvery cast on 
the abdomen : the pectoral fins are brown, 
and of a moderate size : the ventral rather 
small, and of a similar colour : the lateral 
line is strait, and situated nearer to the back 
than to the abdomen : along the lower part 
of the back are ten strong but short spines, 
and beneath the abdomen twelve or thirteen 
others, which are followed by a small anal 
fin. (See plate I. Ichthyology, fig. 1.) 
ACANTHURUS, in natural history, a 
genus of fishes, of the order Thoracici, of 
which the gen. character is, teeth small, in 
most species lobated : tail aculeated on each 
side : general habit and appearance like the 
genus Chadodon, which see. This genus 
consists of such species of the Linnasan ge- 
nus Chaetodon, as, in contradiction to the 
principal character of that genus, have mo- 
derately broad and strong teeth, rather than 
slender and setaceous ones : they are also 
furnished on each side the tail with a strong 
spine. There are twelve species, of which 
the principal is A. unicornis ; this is the 
largest of the genus, growing to the length 
of three feet or more. It is a native of the 
Indian and Arabian seas, in the latter of 
which it is generally seen in large shoals of 
two or three hundred each, swimming with 
great strength, and feeding principally on 
different kinds of sea-weed. This fish was 
described by Grew, in his Museum of the 
Royal Society, under the name of the 
Lesser Unicorn Fish. Fine specimens are 
to be found in the British and Leverian 
museums. 
ACANTHUS, Bear’s Breech, or 
Brank-Ursine, in botany, a genus of the 
Didynamia Angiospermia class, and belong- 
ing to the natural order of Personata?. There 
are ten species: 1. The smooth acanthus, 
with white flowers, proceeding from about 
the middle to the top of the stalk, is the 
species used in medicine under the name of 
Branca ursina, or Brank-ursine. It is a na- 
tive of Italy, about Naples, of Sicily, Pro- 
vence, and the islands of the Archipelago, 
and is cultivated in our gardens, and flowers 
in June and July. Turner (in his Herbal in 
Hort. Kew.) informs us, that it was culti- 
vated in Sion gardens so long ago as the 
year 1551. The leaves, and particularly 
the roots, abound with a soft, insipid muci- 
lage, which may be readily extracted, either 
by boiling, or by infusion. Rectified spirit 
digested on the leaves, extracts from them 
a fine deep green tincture, which is more du- 
rable than that which is communicated to 
spirit by other herbs. Brank-ursine is seldom 
pr ever used medicinally in this country. But 
