New-York tribune., 1901-07-07
TIE ORIGIN OF SPECIES.
fiiE DARwINIAN THEORY STATED BY am
WILLIAM TURNER

WILLIAM TURNER
From the presidential address of the British
Association for the Advancement OF Science
During the evolution of the individual cells
become modified OF differentiated In structure
and function and so long as the differentiatioo
follows certain prescribed lines the rnornhoIoei
cal characters Of the species are preserved We
cah readiiS conceive that, as the process OF spe-
tiallzation is going on, notifications or varia-
lions in groups of cells and the tissues derived
Irom them. Notwithstanding the influence OF
Heredity, may In individual diverse so far
from that which Is characteristic of the sDecies
as TO assume the arrangements found in an
other species. or even In another order. AnatO-
iiistS had indeed, long recognized that varia-
tionS from the customary arrangement OF parts
occasionally appeared and they described such
deviations from the current descriptions as ir-
reguarities.
The Specification of these variations had NOT
been apprehended until flood of light was
thrown on the entire subject by the genius OF
tharles Darwin, who formulated the wide reach
ing theory that variations could be transmitted
by heredity TO younger generations In this
manner he conceived new characters would arise
accumulate and be perretuated, which would In
the course Of time assume specific Importance
New species might thus be evolved out OF or
Sanisms originally distinct from them and their
specific characters would in turn be transmitted
70 their descendants. BY continuance of this
process new species would multiply in many
directions, until at length from one or more
originally simple forms the earth would become
peOpled by the infinite varieties OF plant and
animal organisms which have in past ages In
The Darwinian theory may therefore be
defined heredity modified and influenced by
variability. 1t assumes that there Is an hered-
itary quality in the egg which, il take the
cOmnen fowl for example shall continue to pro-
duce similar fowls Under conditions. OF which
ignorant. which occasion molecular
changes in the cells and tissues of the develop
ing egg. variations might arise in the first in
stance probably slight but becoming intensified
in successive generations. until at length the
descendants would have lost the charac ters OF
the fowl ard have become another species. No
precise estimate has been arrived at. and indeed
one does not see how 1t Is possible to obtain 10.
OF the length of years which might be required
20 convert variation. capable of being trans
mitted. into a new and definite specific char
aCter.
Since the conception of the possibility OF the
evolution of new species from pre-existing forms
took possession Of the minds OF naturalists. at
tempts have been made to trace out the lines
which IL has proceeded The first to give sys
tematic account of what he conceived 10 be the
order of succession in the evolution Of animals
Ernst Haeckel of Jena in we'll known
treatise. Memoirs special departments OF
the subject too numerous TO particularize have
subsequently appeared. The problem has been
attacked along two different lines-the one by
embryologists who have conducted careful and
methOdical inquiries into the stages of develop
ment of numerous forms belonging 70 the two
great divisions of the animal kingdom Inver-
tebrates. well as vertebrates. have been care
fully compared with each other In the bearing
OF their development and structure on their af
frities and descent and the possible sequence
in the evolution of the vertebrate from the In
vertebrate has been discussed
The other method. pursued by paleontolo-
sists has been the study of the extinct forms
preserved In the rocks and the comparison OF
their structure with each other and with that
of the existing organisms In the attempts 20
trace the line of descent. the imagination has
NOT infreduently been called into play in con-
structing various conflicting hypothesis. Though
from the nature OF things the order OF descent
is and without doubt will continue 70 De. ever
a matter OF speculation and not OF demOnstra-
ton the study Of the subject has been valua-
HE intellectual exercise and a powerful stiru-
tan, 10 research We know not regards time
when the fiat went forth-"Let there be life.
and there was life" All we can say is that IL
must have been in the FAR distant past. at
perfod so remote from the present that the mind
fails to grasp the duration OF the interval