Clarksville weekly chronicle. (Clarksville, Tenn.) 1873-1890, 1879-11-29
ABSTRACT OF A LECTURE
Delivered at the n. w. n. Unfver
sitY, by Prof. }. w. Caldwell,
Introductory TO the Course
ON Natural History.

And possibly in like manner the
life period in regard to the various
planets of our system is but one
phase of their history, reached at
some point of time and passed at
some subsequent point.
Biology is the name given to the
science of life, in its grand sweep
embracing the animal and vegeta-
BILE worlds, and in consequence
branching in two directions-botany
treating of the vegetable kingdom,
zoology of the animal. Each of
these is again divided into two de-
partments, viz: physiology and
morphology, the former devoted to
the consideration of function, the
latter of structure.
The organic world is the world OF
organized living bodies. Organiza-
ton seems to be a condition of life
necessary at least to its more dis
tinctive expressions. 1t has been a
question amongst biologists whether
organization preceded life or life
preceded organization. L think we
must understand life as antedating
organization and as being the cause,
not the effect, of organization.
Matter is the seat of various
dynamical affections; there are the
several forms of force denOminated
physical, chemical, vital, occupying
different planes, TO use the phrase
ology of Prof. lie Comte. These
planes rise one above another, and
are evolved successfully, each from
the one next preceding, in the
series. We may not, indeed we do
not, understand the genesis of force,
but the fact is patent that at certain
critical junctures there is a develop
ment of force out of force and an
advance in dynamic character; e. g.,
from the mechanical plane to the
physical, from the physical cCndi-
ton to that of induced chemical
force expressed in chemical COM
pound, and we believe that a mo-
ment of "paroxysmal evolution"
intervenes between the inorganic
condition of protoplasmic matter
and the birth within it of that
higher and more dignified form of
force which we call Life. And-tO
go one step further-it is possible
theory, and one that is more than
suggested by the consideration of
those doubtful forms" at the bot
tom of the scale, that the phase of
animal life has been and may be
superinduced upon the vegetable.
Life, then, we I'M
derstand to be a condition of mat
ter, temporary in its character, dur
ing which it is pervaded by the
highest form of force or energy.
This force tends in the direction of
organization and development,
which latter, as has been well re-
marked, consists in differentiation
The so-called "systemless' protOzo-
ans, the most lOwly representatives
i'm the scale of animal existence, are
least developed that is, least differ
entiated into parts. Indeed, their
structure is entirely homogeneous
organic substance without Organiza-
tion-or at most a system cOnsti-
tuted of one organ, that organ, in
its individual molecules, able to do
and really performing all that the
entire animal is destined to perform
in the way of vital activities and
changes.
When, however, we ascend to
higher and higher forms, the pro-
erosion is marked by the more and
more perfect differentiation" into
dissimilar parts or organs, each one
having a distinct duty or office, and
in general only one, for the discharge
of which it is more and more quail
fed, in accordance with the princi-
pie of the division of labor in our
social systems.
This condition of life is expressed
by various phenomena, the number
and kind depending upon the grade
of the Of ganism. As we know
nothing of the essence of life, we
are (as in the case of matter itself
limited to the consideration of man
ifestations. Life has been defined
to be the sum total of all the activi-
ties characteristic of the particular
living body. We recognize the in
complete and unsatisfactory nature
of this definition, and yet it is not
without its value in directing us to
the most promising points for
geological study, namely: facts, as
also in limiting probable limit to
investigation.
Activity indicates change, and
however tit IOA Alo Va AAAC may NCSNA
the semblance of permanency, one
of the most important and ele-
mentary teachings of modern phys
iology is that life is a condition Of
change-we begin to die the instant
we begin to live. Molecular death
and disintegration go hand in hand
with our every movement, and in
deed they are the very measure of
the rate at which we live Chat is,
act). Every motion of a muscle
produces, Or~is accomplished by,
destruction of muscular tissue; and
every thought Of the mind, every
emotion of the heart, necessitates
nervous waste. We of course do
not assent to the materialistic die.