The daily national Whig. [volume] (Washington, D.C.) 1847-1849, 1847-11-01
From he Nep York Tribune.
THE ANIMAL KINGDOM.
ThIrd Leeture--Dy Prore..or Aga..l1.


produced by the Medusm Difference between The Poyps
and Meduse-Mode OF Growth Of this Species Dissolve
ries Of Sara, krohn. and ChamessoThe Echinodermaa
Interesting Field Of Investigation Open Structure Of
this Species-Mode OF Locomotion Digestive and Crcu.
aiory Apparatus Evidence OF Design in this Department
Of the Work OF Creation.
LADIES AND GENTLEMEN: The last lecture was oc-
cupied in tracing the characteristic features of the
poyps-the lowest Of the radiated animals l show
cd how simple, and nevertheless how beautiful and
well adapted the structure of these animals is. We
find in them only one organ and yet we find almost
all the functions Of animal life. That one organ is
the stomach.-an ample cavity with two openings, a
mouth and hole at the bottom Of the sack empty
ing into the general cavity of the body; thus the
food, when dgesied, is mixed with water, which
constantly fills the general cavity of the body This
mixture of sea-wuter is constantly set in motion by
capillary ella, or hair-like appendages covering the
whole surface OF the internal cavity, as well Us the
internal cavity of the entacles and by the partitions
which from the external well of the animal to-
ward the centre Of TINT cavity thus filled with water,
which is then kept in motion In different currents,
some ascending, others descending, that there Is
constantly kept up circulation Of the digosied food
The walls of the animal permeable 10 this liquid
that portion which is nuritive remains in the walls
of the animal, while the water, which has been the
vehicle for this food is pushed out by the contrac-
ton OF the animal
There are two exits for the food either through
the mouth again, by the small openings in the
tentacles. The water which fills the general cavity
enters also through the tentacles and the mouth
alternately through one or the other. But there
are muscular fbres similar to the flesh OF higher ami
mails, which can be elongated by gradual contraction
expansion this cavity can be alternately shut so
that by the contraction OF the mouth the introduce
ton of water may be allowed or prevented. The
nft he hc Ea,,t tha
cavity by the contraction of the lower opening OF
the intestinal cavity; and again, the tentacles can
contract ut their end, and prevent the water from
escaping: and while the dgested food is moving with
the water within the cavity, with the entacles thus
contracted, nothing escapes-but after the nutritve
portion of the food has been absorbed by the walls
of the animal, then the water is allowed TO escape
through its mouth, well the other opening. An
agency or influence is undoubtedly exerted upon the
surface of the animal by the surrounding water,
which may be compared to the respiration of ami
mails that live in the water There is something SINH
lar TO bronchial respiration in some of the lower ami
mails especially the molisca, where the action Of
the wnter acts the fluids in the animals, und pro-
duces upon them change which enables the fluid
TO become portion of the living creature These
changes are very complicated and not all fully un-
derstood. There is much room for investigation,
with reference to the changes which the food under
goes, in order that il may become portion Of the
living animal. What is more wonderful than what
we every day-a COW grazing, and turning the
grass into brain, muscles, bone That is constantly
going on; and different animals produce the same
changes upon common food with different organs,
but in all the same result. Thus the same food is
transformed in one case into the body Of the hare
in another into that OF the deer and in another into
the body of the elephant. With the same food these
animals only reproduce, but create, as it were,
their bodies under the influence of the primitive
material principle which is the cause OF their exist
ence. ss
Another system OF organs existing in the polypi
the ovnries hanging in punches either in the in
ternal cavity, or outside on the tentacles. These
forms have been the foundation of the two great
divisions of the polypi, namely, the actinoidG, the
name derived from the Greek word for tray" and
the hydroida, because these animals resemble that
which has been called the hydra name re-
minding you Of fearful animal. Thus these harm
less minute, almost microscopic animals, have re-
ceivcd that formidable name.
You see here (pointing to a diagram) eggs forming
on the outer side. Some are not isolated as in this
case. In many instances the eggs hang in punches,
as you have them, for instance in that diagram.
then alluded TO other differences in polypi where
some were isolated individuals and others combined;
the latter budding one and the same STEM thus
forming three large groups Of individuals united by
their base. 1t is peculiarly of polypi to be fixed
on the soil. There are no free swimming animals
among them. Some are attached to other bodies n,
the bottom Of the sea- Some are fixed at will, or
at will from their location; but there are none
among them who swim freely in the waters In this
respect many Of them have some likeness TO plants
and were indeed long mistaken for plants. Even SO
late as the middle of the eighteenth century natu-
rasts quarreled about the vegetable animal nature
Of poyps But 1t is now fully understood that they
belong to the animal kingdom; while, on the other
hand many organizations which belong truly to the
vegetable kingdom have been introduced among the
polyp, and must of course be rejected from that
class and be again classed among the plants There
is, indeed some difficulty in distinguishing some Of
the lower types of plants and animals have already
alluded to one grand distinction between them. The
existence of stomach is chief characteristic of an
animal, and no being should be introduced into the
animal Kingdom in which stomach does not exist
But as there is great difficulty in ascertanng in some
OF the lower animals whether there is an amentary
cavity or not, we take other characteristics by
which they can be distinguished; and we have now
very remarkable test by which we can determine
whether an organized being is plant animal.
In the mode OF respiration we may by chemical ana
iysis, discover whether animal or plant is before
u.s. All animals in respiration assimiate oxygen and
reject carbon, while plants assima,e carbon and re.
ject oxygen. There is thus constant antagonism
between the animal and vegetable Kingdom All ami
mails would die were not for the breathing of plants
and all plants would perish did animals cease to re-
spire. The antagonsm is such that the whole amount
OF animals living, now consume precisely the amount
ofoxygen which plants expc during the night; and
by this antagonism between the animal and vegeta
Bile Kingdom, this constant and unyarying eauilibr-
um OF the atmospheric air is maintained Now when
we want to know whether We have before us mi
croscopic animal or microscopic plant all we have
10 do is to examine the of the gas absorbed or
expelled in respiration.
Another test may be us certain That test consists
IN Inc examination Of the egg, The eggs of all ami
inals, without any exception from the polyp up to
the mannalia are Identical There is not the slight
est difference in their slrucuein the internal and
minute structure Of the eggs Of all classes of the ami
NAL Kingdom. There are differences in size but not
In structure. The egg Of fish is full of granulcs