The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1838-08-10 00:00:00

MECHANICS' INSTITUTION.

LECTURES ON THE STRUCTURE AND HISTORY OF THE
ARTICULATED MOLLUSCOUS CLASSES OF ANIMALS.

On Saturday evening Dr. Grant delivered his second
lecture upon the articulated classes of animals.
The waters of the globe abound with tenfold more ani-
mated beings than are to be found in the atmosphere or upon
the surface of our planet. The air, earth, and water are
peopled with their own inhabitants, all duly organised with
their particular elements. Every altitude as well as every •
latitude has its own species of organization. Not only do we
find animals thus beautifully organized for the habitation of
the waters, but we observeitharthose which burrow in the
earth, and those which move to or fro upon its surface, or fly
in the air, are alike enabled to respire oxygen. Indeed when
we consider the influence of oxygen upon the animal econo-
my, we are surprised that there should be organised bodies
so high as articulated animals siihich possess no external or
internal organs for the purposes of respiration; singular to
say, there are beings which are capable of living for a con-
siderable period, in health and vigour, without coming once
into contact with atmospheric air.
It is profitable some times to contemplate the forms of
organic bodies which occur around us on the surface of our
globe. It may be hideous to some to contemplate some of the
mammalia, the reptiles, or the amphibious animals, their
habits being so repulsive as to excite feelings of disgust.
These feelings, however, vanish as we begin to approach
nearer• to their bodies and view their perfect adaptation to the
circumstances of their being. Whenever we observe the
flowers of the forest, we perceive that they swarm with living
beings necessary to their existence. There is not a plant in
the forest which is not distinguished by its parasitical
animals as well as by animals which are higher in the scale.
Some are organized to creep to and fro upon the surface of
the plants and to suck the superfluous juices formed in such
abundance by nature. Nothing in nature is ever lost ! We
observe indeed that not only are the exterior parts of the
plants provided with their own special inhabitants, but that
different portions of the interior have their special animals
to feed upon them. Seine plants prey upon animals; first
attracting them by their fragrance and then detaining them
in their grasp until they have derived from their bodies the
nutrition which they are calculated to afford. Each animal,
from the highest down to the lowest, is in fact a menagerie,
maintaining within itself myriads of different beings, many
of which, but for the progress of curious investigation and
modern invention, would have escaped observation. Man
was not permitted to see the beauties of the creation until,
by the progress of the arts, he was given another sense. By
the microscopic powers he has brought animals and plants
within his knowledge, which, otherwise, would have
escaped his investigations. It has been found that
most of the fluids of animals contain their own peculiar
inhabitants. These are classed i❑ one great heteroge-
neous mixture denominated entozon or parasitical ani-
malculm. Indeed these beings have been distinguished by
various names. The thin fluids, of the eye have been found
to contain them. Hydatids have been found in the aqueous
humour of the eye of the horse, as indeed have animals of
great magnitude. As we pass to the internal regions we find
that the alimentary canal supports millions upon millions of
creatures. If we examine the passages which lead from the
intestines into the different glands, such as the pancreas and
the liver, we find, as might be expected, that they.swarm with
different tribes of living beings. We find in the blood-
vessels—nay, in the coats of the hlood-vessels and in the
heart itself, minute parasitical animalculm. We find them
within the cavity of the abdomen, and in the substance of
the liver. Now we find not only that these parts, but that
each- portion of the animal, has its different animalculm,
which have but a limited range in the body. It is extremely
difficult to say whether the same animalculm occur in diffe-
rent species of anienals. If we examine the most active
muscles of the body, we see that the muscular system from
one end of the body to the other is permeated large entozoa.
We observe even that the delicate substance of the brain is
capable of affording nutriment to myriads of the entozoa.
The feathered tribe, which one would think escape contamina-
tion in their voyages through the airy regions of the sky, also
have their specific -animalculm. amphibicm contain
them in great nun:lints. We see them in and upOn all-parts
of the bodies of fishes,—for here it is that nature raises them
in the greatest perfection. We find them on all parts of the
exterior of the body—hanging from the exterior of the eve,
from the gills, the fips, and all parts of the neck,—in sliort
from every part where the skin is capable of being punctured
so as to afford them subsistence. Notwithstanding this the
fish passes on without being in the least injured by what it is
supporting. Passing to the inferior molluscous animals, we
find upon them an abundance of parasitical animalculm.
Many of them are indeed animalculse from their extreme
minuteness. Nay, observations have been made down as
low as the articulated animals themselves, and, what may
seem incredible, the parasitical entozoa support other ani-
malcules within. themselves. For instance, those which are
taken from the aqueous humours of the eyes support other
animalculm within them,—so that there seems to be no end
of life so far as the microscope has assisted our labours. It
is curious to observe by what means nature has enabled the
different forms to provide for their own existence. We have
seen that the serpentine form is the best calculated for insi-
nuating itself through the texture of the veins and all the
curves in the animal bodies through which the animalculm
must pass to obtain their nutriment. We therefore find that
in the intestinal worms, the serpentine form of the body is
best adapted for their wants. There are many entozoa, how-
ever, which assume a globular form. For instance, if the
animal is to be placed in the nutritious, warm substances of
the body, it requires not to change its situation ; there is. no
necessity to give it the power of locomotion. Indeed, it
would be dangerous to give those eutozoa, which prey upon
the brain, that serpentine form which would enable them to
wend their way through the fine fibres of which it is composed.
These are, therefore, most properly of the spherical form—
that is to say, they have a bladder-shaped vessel filled with
some fluid, with a transversely marked neck. When we
open the liver of the rabbit, and look at the great number of
animalculm which we see alive, we can perceive their mus-
cular fibres, and heads with four sartorial ducts arranged
around. The creature has a number of horny spines for
the purpose of irritating the surface of its prey, in order
to obtain a constant supply of fresh nutriment. The
horny spines occur in the brain itself, in connection
with the flower-headed animalculm met with there. A species
of entozna of this shape is found in the brain of the sheep,
which occasions the animal some inconvenience. It will be
said how came they into the interior of the brain of a sheep
seeing that there is no external passage there. The blood is
the only medium through which they could get there. This
explanation is, however, more specious than satisfactory, for
if we examine them in the youngest state we shall find that
they never could have entered the brain in that manner, be-
cause the parietes of the capillary vessels are perfectly inca-
pable of allowing the creatures to pass through them. In these
animalculm there is a fine adaptation for the medica in which
they occur. We observe, however, that although these
simple globular forms have generally distinct heads, there
are several which defy the most careful examination to shew
by what means' they are able to obtain their food, for the
most careful analyzation has not yet discovered a single ab-
sorbent power about them.
The tape-worms are composed of aggregates of a number
of beings whose heads are surrounded by sartorial ducts with
a central aparture. The separating of a part will thus be of
no importance to the existence of the worm. These worms
have been met with 100 feet in length, We find them some-
times occupying nearly the whole bulk of the alimentary
canal. The herbivorous quadrupeds and those which are
most subservient to man are those upon which we have made
the greatest observation. Upon examining the sheep we find
that its intestines contain a small animal similar to the pla-
naria found in fresh water and rivers. Quadrupeds partaking
of food moistened with river water• are found to be attended
by a certain kind of paiasitical animals. Some have sup-
posed that as these creatures are taken in with the food into
the canal that they find their way into the ducts and thus get
into the central substance of the liver, where meeting with
richer fond they attain a greater size. The forms of these ani-
mals vary according to the situations they are intended to
fill in the body or the hardships they live to sustain, and in
every instance we find them admirably contrived for such a
purpose. The form of these creatures which we find attached
to the external part of the bodies of animals is again different.
The learned gentleman then explained the structure of these
entozoa as well as their various organs, but we feel that we
must refer those' of our readers who are curious in such mat-
ters to the very able works now publishing by the Professor,
on the comparative quantity of the various animals existing
in the world. After minutely describing a species of entozoa
found by Captain Scaresby on the eye of a shark which he
had dissected, Mr. Grant concluded as follows. We thus see
that there is nothing lost which is capable of affording nutri-
ment to the organic beings, and while they serve the purpose
of stimulating to cleanliness, we observe likewise that they
are confined to those parts of the intestinal regions in which
they occur, for there are-many of these creatures which never
make their appearance through the universe, but in these
deeply seated organs to which there is no access found
without.

This lecturer, like the preceding, was illustrated through
out with valuable diagrams.

SELECT EXTRACTS.

THE.EDGEWORTH FAMILY.—The late eminent Mr. Edge-
worth had four wives • of these the last is living, and is the
mistress of the establishment at Edgeworth's Town. She
has a son, a daughter-in-law (who is Spanish,) and a grand-
child in the finally, besides whom there are a daughter of
another of the wives, an aged and venerable sister of Miss
Edgeworth's mother, and Miss Edgeworth herself, who is the
daughter of the first wife.—The American in Ireland.
LEGISLATION.—If acts of parliament were, after the old
fashion, penned, and by such only as perfectly knew what the
common law was, before the making of any act of parliament
concerning the matter, as also how far the former statutes
had provided remedy for former mischiefs and defects dis-
covered by experience, then should very few questions in law
arise, and the learned should not so often perplex their heads
to make atonement and peace by construction of between
insensible and disagreeing " w ords," "sentences," and "pro-
visoes," as now they do.—Coke.—[lf this were so in Coke's
time, how much more forcibly and voluminously does it
apply now.
INDIAN POISON.—One of the mast remarkable vegetable'
,productions is a poison used for destroying animal life. It
is grown only by the Abors, a mountain tribe, inhabiting the
banks of the Sampoo. Its cultivation is kept a great secret,
and they carry their precaution so far as to boil it before
leaving their country, so as to destroy all vegetation. It is
brought into Suddia by the Abors, tied up in little bundles,
and has the appearance of a small fibrous root. It is pre-
pared for use by pounding the roots to powder, and mixing it
up into a paste with tlje juice of a tree called Otenga, so as
to give it tenacity, and make it adhere to the arrow head. So
fatal are its effects, that even a scratch from an arrow so poi-
soned is followed by almost instant death. This is the poison
used by all tiger.killers for poisoning their arrows.
TRAVELLERS BY STAGE COACHES.—Upon making a cal-
culation for the whole number of stage coaches that possessed
licenses at the end of the year 183-1, it anpears that the means
of conveyance thus provided for travelling are equivalent to
the conveyance, during the year, of one person for the dis-
tance of 597,159,420 miles, or more than six times the dis-
tance between the earth and the sun. Observation has
shown, that the degree in which the public avail themselves
of the accommodation thus provided, is in the proportion of
9to 15, or 3-sths of its utmost extent. Following this pro-
portion, the sum of all the travelling by stage coaches in
Great Britain may be represented by 358,295,652 miles. If
we exclude from the calculation all very young children, as
well as persons who, from their great age and bodily infirmi-
ties, are unable to travel, there will probably remain in
England 10,000,000 persons by whom that amount of travel-
ling might be accomplished; but it is well known that a very
large proportion of the population are not placed in circum-
stances that require them to travel; and, if even it were
otherwise, that they would not avail themselves of a mode of
conveyance so comparatively costly as a stage coach. We
shall probably go to the utmost extent in assuming, that not
more than 1-sth, or 2,000,000 of persons, travel in that man-
ner; and it places in a strong point of view the activity
which pervades this country, when we thus arrive at the
conclusion, that each of those persons must, on an average,
travel on land by some public conveyance 180 miles in the
course of the year. This calculation is exclusive of all tra-
velling in post chaises, in private carriages, and by steam
vessels, the amount of which there are not any means of esti-
mating. It affords a good measure of the relative import-
ance of the metropolis to the remainder of the country, that,
of the above number of 597,159,420, the large proportion of
409,052,644 is the product of stage coaches, which are licen-
,srehdetolireuennsferso,mwLhoienhdohnavteo
fvoarrmi oeuds
tphaertsgroofunthdewokrkingodfotmhe.
calculations, include all public conveyances proceeding be-
tween one part of England and another part of England, as
well as those conveyances which travel between England
and Scotland, but not such as begin and end their journeys
in Scotland ; and their travelling in Ireland is wholly ex-
cluded.—Progrest of the Nation.