Memphis daily appeal. [volume] (Memphis, Tenn.) 1847-1886, 1867-02-24

life, all showing one and Jhe same
structure. l like to insist upoI
these facts, which are the mos
brilliant results of modern progress
or science, because you see at once wha
bearing they have upon the question o.
the origin Of these things. II we have
! identical structures under the most di-
| versified conditions of existence, these
| external things which act upon living
| beings cannot have by,en the cause which
! has pro iuced such unity in plan. The
| unity of plan-that ideal common basis
of animais-must be derived from some
| thing higher than the conditions in
/ which these animals live, when we lind
/ that Notwithstanding these diversified
| conditions, the animals present one an0
! the same plan and structure. Applause.
The next type is that of vertebra. II
| is one which has a special interest
| for us for We belong there laughterl !,
| and with Us all the animals which have
backbone, all the animals which have
an internal solid axis so arranged as to
surround two distinct cavities in which
the various organs of the body are in
closed, one cavity below that axis in
which all these parts or all those sys-
tens OF tie organs are contained by
which life is maintained in its normal
condition. These are the organs OF
digestion through which food is assimil-
ated and transformed for the subsistence
of the body, the organs OF breathing III
which this assimilation is fostered, the
organs Of circulation through which
the Sesult Of these operations is
circulated through the system, and
also the organs of reproduction. All
these organs by animal life is simply
k1su 4
cavity of the body, while an upper cavity
contains organs which establish the rel3-
tions between the animals and the sur
rounding world. In that upper cavity is
contained, in the anterior part of the
body, the brain, and ia the middle and
posterior parts of the body the prolOnga-
lion Of the brain which we call the spinal
marrow. From it arises the nerves,
which are scattered through all parts OF
the body, and send sensibility and also
receive impressions from the outside.
To this center is attached the organs OF
the senses, and which communicate di-
rectly with the central mass OF the ner-
vous system. All these parts are con-
tanned in the upper cavity OF the
body. and the whole is surrounded
by flesh and inclosed in a skin,
and whatever be the type Of vertebra
which we take for examination, whether
man or quadruped, bird, reptile, snake,
turtle, or fish, all have the same ldenti-
cal structure, and these structures differ
only in the form and complication of the
execution, but in no way does the plan
differ in the slightest degree. a shark,
or a perch, u man, or q bird, have the
same Identical plan of structure, and we
could make a cut across their body,
through the neck, the head, the chest, or
the tail, and compare one with the other,
and we would find that the sections had
the same organs which had the same re-
lations to one another; and if We COM
pared one section in the same body with
The other, a cut made through the head,
or through the middle, or through the
hind part of the part again, we
would find the same relations, so
wonderful is the idea which is mani
tested in this iUnumeTable variety. And
now let me show you that this is not a
fanciful assumption. The professor here
drew the form of fish on the black
board. We have here the backbone,
here the upper spine of the skeleton,
here also, tie ribs, here the head, the
mouth, the base of the organs gf the
senses, the eyes, the nOstrils, and so on.
Suppose we make section across the
body here through the center OF the
body, or here through the head, or here
through the tail, there will be differ
enee in the relative dimension of the
parts, but these will ba no difference
in the relative position OF these
PARTS, and in the nature Of these
parts. suppose ! commence with the
section across the middle OF the body.
The first thing we fiud la ths
Al. al -fa o1., lsaf
have these spires, which are in reality an
arch covering a cavity we have here
below the ribs, which are another arch
inclUsing another cavity THIS Is the
lower cavity which contains, as ! haye
said. the organs Of digestion, the intes-
tines, liver, and the like. In the ante
rio, Dsst Of the body we should find the
heart, in the p.i4lle regiOn we should
find the large vessels Whlcn r4n parallel
10 the backbone, in the upper cavity We
should End the spinal marrow, and on
the outside OF tnRt the masses Of tiesh
which are by the skin. and now in the
tail We shOGld haze exactly the same
thing only that ths central BACKBONE is
surmounted by a similar arch, The
intestines do not extend here except
in the form of vessels and nerves, and
here we LRVs 2 nrolOngatiOn of the
spinal marrow, an5 we have fesh around
here as before. Now, in the head is the
difference. This upper portion IS largely
developed, in OmpArisGE 9Th the lower
poftiob This upper portion becomes tie
Skull. inside 4 the extensive mass OF
the brain. This IS the base Of the skull.
Instead of ribs, we have the lower jaw
attached. Upon the sides OF the skull
we have masses of flesh, which keep in
motion these parts which are on the side,
and the whole is surrounded by skin, as
here. So that the Wnuie dltierepce Is
that the cavity Of the intestines
is reduced to cavity Of the
mouth oRening outside, just as the ali
mentaTy canal l. 8 continuation OF the
cavity Of the mouth and the spinSI mar-
row OF the brain. The brain , only an
enlarged portion Of the spinal marrow,
or, to reverse II, the sPingi marrow is a
modification of the brain extending
through the body. So that you see that
NV assertion is true, that in whatever
region we may make a section to exam
inc tho relative positions Of the oIgHus OF
lhe vertebra We 6na the organs identical,
bearing the same relation toons sa6.Aer.
III tisis would permit ! could readily
show YOU thAl whatever the form OF
al auIinaI, whether il be FISH or q SER
psnt whether lizard or turtle, o. {
bird, the felatiQp Of the parts are again
the same, and the differences are chiefly
differences in form and development.
And il is in consequence OF this great
similarity that the idea has been started
that ali tnsss Gnipals may be derived
one from the other; th4t 81 these ami
mails may be the resaIt OF Successive
modl6eatioHs Of the few. You see on
the ONE band We hRVe these uniform
conditions which Sustain the HGst
Diversified forms; thea again we have
this unity Of plan, which seems TO be in
contradiction to the variety Of influences
under EGics these animals exist. Then
again We have an extraordinary diversity
OF forms, which seem TO Indicate the
most diversified organs; and yet
snch is Lhe similarity among
lheSe various things thai they seen2~to
he only a modification one Of the other
No wonder, therefore, that investigators
should make it their special object to
stiI.ly these things, and that they should
differ 10 their opinions so much that
there should be those who capnot con-
ceiye the cause of this diversity, unl6ss
n he the immediate manifestation of q
snecial creative act on the part of being
6nahla of producing at once perfect be-
InRs. whiis Others more inclined, per-
hsps. to follow devslnp4eRt and pro-
a,rasI than 10 look at first cause Of all
9bings- would rather have every
l6inR derived from a few primary
forms which hsye undergone ex-
traordinary changes in TIE course Of
time. To this subject / shall return in
"a, last lecture. l only point at present
to the bearing which these investigations
Of structural relations hsye upon the
0nestion Of origin, upon the question oi
diversity, aud upon the question of unity
IN diVefsity. For all things that exist
| in san1e n6int Gf view are alike, chiefly
by he Unity which prevails throughout
nature; while from another Peiat al
view everything seems different and
when we come 70 consider what may De
the origin of all things, we are at once
| led. on the one hand, to the evidences o
the workings OF one mind, and, on the
other hand. TO the eyer-cbanging con
Gitions under which everything lives