ISE 
soon return into a warmer atmospliere, it 
would destroy life just in the same manner 
as many poor people, wdio have no com- 
fortable dwellings, are often destroyed from 
being too long exposed to the cold in win- 
ter. Upon the first application of cold the 
irritability is accumulated, and the vascular 
system therefore is disposed to great action ; 
but after a certain time all action is so 
much diminished, that the process, what- 
ever it be, on whicli tiie formation of the 
irritable principle depends, is entirely lost. 
See Dr. Crichton on Mental Derangement 
for more on this subject. 
ISATIS, in botany, a genus of the Tetra- 
dynamia Siliculosa c!a?s and order. Natu- 
ral order of Siliquosae or Cruciformes. Cru- 
ciferae, Jussieu. Essential character: silicle 
lanceolate, oiie-celled, one-seeded, decidu- 
ous, bivalve ; valves navicular. There arc 
five species, of which I. tinctoria, dyer’s 
woad, is a biennial plant, with a fusiform, 
fibrous root : stern upright, round and 
smooth, woody at bottom, branched at top ; 
stem leaves from two to three inches long, 
and scarcely half an inchin breadth ; flowers 
small, terminating the stem and branches 
in a close raceme ; both corolla and calyx 
yellow; petals notched at the end; seed 
vessels on slender peduncles, hanging down, 
chesnut coloured or dark brown, shining 
when ripe, of an oblong elliptic form, com- 
pressed at top and on the sides into a sharp 
edge, swelling like a convex lens in the 
middle ; cotyledons ovate, fleshy, piano 
convex ; radicle subcylindrical, bent in up- 
wards. It is a native of most parts of Eu- 
rope. Woad is much used by dyers for its 
blue colour ; it is the basis of black and 
many other colours. 
ISCHjEMUM, in botany, a genus of the 
Polygamia Monoecia class and order. Na- 
tural order of Gramina, or Grasses. Gra- 
mine®, Jussieu. Essential character: her- 
maphrodite calyx ; glume two-flovyered ; co- 
rolla tvvo-valved; stamens three; styles 
three; seed one: male, calyx and corolla 
as in the other ; stamens three. There are 
eight species. 
ISERINE, in mineralogy, a species of the 
Menachine genus : it is of an iron-black, in- 
clining a little to the brownish-black; it 
pccurs in small, obtuse, angular grains, and 
in rolled pieces, vyith a rough glimmering 
surface. Internally it is glistering, and its 
lustre is semi-metallic. Specific gravity 
4.5. Before the blow-pipe, it melts into a 
blackish-brown coloured glass, which is 
ISI 
slightly attracted by the magnet. It is 
composed of 
Oxide of menachine 59.1 
iron 30.1 
uran 10.2 
99.4 
Loss 6 
100.0 
It bears a great resemblance to iron- sand, 
in colour, but in specific gravity it ditfers, as 
also in its being very slighly attractable by 
a powerful magnet. It is found on high 
mountains in Germany. 
ISERTIA, in botany, a genus of the 
Hexandria Monogynia class and order. Es- 
sential character : calyx coloured, four 
or six-toothed ; corolla six-cleft, funnel 
form ; pome sub-globular, six-celled, many 
seeded. There is but one species, viz. I. 
coccinea, a tree with a trunk ten or twelve 
feet in height, and about eight inches iq 
diameter ; the bark is wrinkled, and of a 
russet colour ; the wood light^ and of a 
loose texture ; branches quadrangular, 
straight, with opposite branchlets, chan- 
nelled and covered with a russet down ; 
each branchlet has three flowers, of which 
that in the middle is sessile ; calyx purplish ; 
tube of the corolla two inches long, of a 
bright red ; border yellow, covered on the 
inside with hairs of tlie same colour ; fruit a 
succulent red berry or pome, the size of a 
cherry, sweet and good to eat. The wood 
is bitter ; a decoction of the leaves is used 
by the Creoles in fomentations. It is com 
mon in the island of Cayenne ; and on the 
continent of Guiana, flowering and bearing 
fruit a great part of the year. 
ISIN GLASS, used in medicine and do- 
mestic economy, is a preparation formerly 
made only from a fish named huso, a spe- 
cies of the Accipenser genus. We have, in 
the sixty-third volume of the transactions of 
the Royal Society, a full account of the 
mode of preparing this substance, of which 
>ye shall give an extract. 
The sounds, or air-bladders, of fresh wa- 
ter fish in general, are preferred for this 
purpose, as being the most transparent, 
flexible, delicate substances. These con- 
stitute the finest sorts of isinglass ; those 
called book and ordinary staple are made of 
the. intestines, and probably of the perito- 
naeum of the fish. The belluga yields the 
greatest quantity, as being the largest and 
most plentiful fish in the Muscovy rivers ; 
