British Museum - "The Babylonian Legends of the Creation"

Louisa Stuart Costello - "Béarn and the Pyrenees"

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Annual Bibliography of Commonwealth Literature 2007
This paper argues that discourses of love in Ghanaian market literature for youth offer a view into complex negotiations of agency and empowerment. Drawing on Deborah Durham's notion of youth as "social `shifters'" and Francis Nyamnjoh's conception of the "interconnectedness" of agency, I take Ghanaian market literature as one specific case of how African literature for youth foregrounds questions of continuity and change as African societies enter into increasingly complex global relations. In this literature for youth, received notions of love, often constructed out of impressions from American pop and hip hop music, carry new notions of agency that compete with existing "domesticated" forms. Authors like Ike Tandoh and Evelyn Tay employ discourses of love to offer youth alternative avenues for empowerment in a context of socio-economic disenfranchizement. In a creative process of "straddling", this writing both reveals and reproduces the contradictions that obtain in youth configurations of agency.

On the Genesis of Species

S >> St. George Mivart >> On the Genesis of Species




Now, considering the number of instances adduced of sudden modifications in
domestic animals, it is somewhat startling to meet with Mr. Darwin's
dogmatic assertion that it is "a _false belief_" that natural species have
often originated in the same abrupt manner. The belief _may_ be false, but
it is difficult to see how its falsehood can be positively asserted.

It is demonstrated by Mr. Darwin's careful weighings and measurements,
that, though little used parts in domestic animals get reduced in weight
and somewhat in size, yet that they show no inclination to become truly
"rudimentary structures." Accordingly he asserts[94] that such {103}
rudimentary parts are formed "suddenly, by arrest of development" in
domesticated animals, but in wild animals slowly. The latter assertion,
however, is a _mere assertion_; necessary, perhaps, for the theory of
"Natural Selection," but as yet unproved by facts.

But why should not these changes take place suddenly in a state of nature?
As Mr. Murphy says,[95] "It may be true that we have no evidence of the
origin of wild species in this way. But this is not a case in which
negative evidence proves anything. We have never witnessed the origin of a
wild species by any process whatever; and if a species were to come
suddenly into being in the wild state, as the Ancon Sheep did under
domestication, how could you ascertain the fact? If the first of a
newly-begotten species were found, the fact of its discovery would tell
nothing about its origin. Naturalists would register it as a very rare
species, having been only once met with, but they would have no means of
knowing whether it were the first or the last of its race."

To this Mr. Wallace has replied (in his review of Mr. Murphy's work in
_Nature_[96]), by objecting that sudden changes could very rarely be
useful, because each kind of animal is a nicely balanced and adjusted
whole, any one sudden modification of which would in most cases be hurtful
unless accompanied by other simultaneous and harmonious modifications. If,
however, it is not unlikely that there is an innate tendency to deviate at
certain times, and under certain conditions, it is no more unlikely that
that innate tendency should be an harmonious one, calculated to
simultaneously adjust the various parts of the organism to their new
relations. The objection as to the sudden abortion of rudimentary organs
may be similarly met.

Professor Huxley seems now disposed to accept the, at least {104}
occasional, intervention of sudden and considerable variations. In his
review of Professor Koelliker's[97] criticisms, he himself says,[98] "We
greatly suspect that she" (_i.e._ Nature) "does make considerable jumps in
the way of variation now and then, and that these saltations give rise to
some of the gaps which appear to exist in the series of known forms."

[Illustration: MUCH ENLARGED HORIZONTAL SECTION OF THE TOOTH OF A
LABYRINTHODON.]

In addition to the instances brought forward in the second chapter against
the minute action of Natural Selection, may be mentioned such {105}
structures as the wonderfully folded teeth of the labyrinthodonts. The
marvellously complex structure of these organs is not merely unaccountable
as due to Natural "Selection," but its production by insignificant
increments of complexity is hardly less difficult to comprehend.

Similarly the aborted index of the Potto (_Perodicticus_) is a structure
not likely to have been induced by minute changes; while, as to "Natural
Selection," the reduction of the fore-finger to a mere rudiment is
inexplicable indeed! "How this mutilation can have aided in the struggle
for life, we must confess, baffles our conjectures on the subject; for that
any very appreciable gain to the individual can have resulted from the
slightly lessened degree of required nourishment thence resulting (_i.e._
from the suppression), seems to us to be an almost absurd proposition."[99]

[Illustration: HAND OF THE POTTO (PERODICTICUS), FROM LIFE.]

Again, to anticipate somewhat, the great group of whales (Cetacea) was
fully developed at the deposition of the Eocene strata. On the other hand,
we may pretty safely conclude that these animals were absent as late as the
latest secondary rocks, so that their development could not have been so
very slow, unless geological time is (although we shall presently see there
are grounds to believe it is not) practically infinite. It is quite true
that it is, in general, very unsafe to infer the absence of any animal
forms during a certain geological period, because no remains of them {106}
have as yet been found in the strata then deposited: but in the case of the
Cetacea it is safe to do so; for, as Sir Charles Lyell remarks,[100] they
are animals, the remains of which are singularly likely to have been
preserved had they existed, in the same way that the remains were preserved
of the Ichthyosauri and Plesiosauri, which appear to have represented the
Cetacea during the secondary geological period.

[Illustration: SKELETON OF A PLESIOSAURUS.]

As another example, let us take the origin of wings, such as exist in
birds. Here we find an arm, the bones of the hand of which are atrophied
and reduced in number, as compared with those of most other Vertebrates.
Now, if the wing arose from a terrestrial or subaerial organ, this abortion
of the bones could hardly have been serviceable--hardly have preserved
individuals in the struggle for life. If it arose from an aquatic organ,
like the wing of the penguin, we have then a singular divergence from the
ordinary vertebrate fin-limb. In the ichthyosaurus, in the plesiosaurus, in
the whales, in the porpoises, in the seals, and in others, we have
shortening of the bones, but no reduction in the number either of the
fingers or of their joints, which are, on the contrary, multiplied in
Cetacea and the ichthyosaurus. And even in the turtles we have eight carpal
bones and five digits, while no finger has less than two phalanges. It{107}
is difficult, then, to believe that the Avian limb was developed in any
other way than by a comparatively sudden modification of a marked and
important kind.

[Illustration: SKELETON OF AN ICHTHYOSAURUS.]

How, once more, can we conceive the peculiar actions of the tendrils of
some climbing plants to have been produced by minute modifications? These,
according to Mr. Darwin,[101] oscillate till they touch an object, and then
embrace it. It is stated by that observer, "that a thread weighing no more
than the thirty-second of a grain, if placed on the tendril of the
_Passiflora gracilis_, will cause it to bend; and merely to touch the
tendril with a twig causes it to bend; but if the twig is at once removed,
the tendril soon straightens itself. But the contact of other tendrils of
the plant, or of the falling of drops of rain, do not produce these
effects."[102] But some of the zoological and anatomical discoveries of
late years tend rather to diminish than to augment the evidence in favour
of minute and gradual modification. Thus all naturalists now admit that
certain animals, which were at one time supposed to be connecting links
between groups, belong altogether to one group, and not at all to the
other. For example, the aye-aye[103] (_Chiromys Madagascariensis_). {108}
was till lately considered to be allied to the squirrels, and was often
classed with them in the rodent order, principally on account of its
dentition; at the same time that its affinities to the lemurs and apes were
admitted. The thorough investigation into its anatomy that has now been
made, demonstrates that it has no more essential affinity to rodents than
any other lemurine creature has.

[Illustration: THE AYE-AYE.]

Bats were, by the earliest observers, naturally supposed to have a close
relationship to birds, and cetaceans to fishes. It is almost superfluous to
observe that all now agree that these mammals make not even an approach to
either one or other of the two inferior classes.

{109}
In the same way it has been recently supposed that those extinct flying
saurians, the pterodactyles, had an affinity with birds more marked than
any other known animals. Now, however, as has been said earlier, it is
contended that not only had they no such close affinity, but that other
extinct reptiles had a far closer one.

The _amphibia_ (_i.e._ frogs, toads, and efts) were long considered (and
are so still by some) to be reptiles, showing an affinity to fishes. It now
appears that they form with the latter one great group--the ichthyopsida of
Professor Huxley--which differs widely from reptiles; while its two
component classes (fishes and amphibians) are difficult to separate from
each other in a thoroughly satisfactory manner.

If we admit the hypothesis of gradual and minute modification, the
succession of organisms on this planet must have been a progress from the
more general to the more special, and no doubt this has been the case in
the majority of instances. Yet it cannot be denied that some of the most
recently formed fossils show a structure singularly more generalized than
any exhibited by older forms; while others are more specialized than are
any allied creatures of the existing creation.

A notable example of the former circumstance is offered by macrauchenia--a
hoofed animal, which was at first supposed to be a kind of great llama
(whence its name)--the llama being a ruminant, which, like all the rest,
has two toes to each foot. Now hoofed animals are divisible into two very
distinct series, according as the number of functional toes on each hind
foot is odd or even. And many other characters are found to go with this
obvious one. Even the very earliest Ungulata show this distinction, which
is completely developed and marked even in the Eocene palaeotherium and
anoplotherium found in Paris by Cuvier. The former of these has the toes
odd (perissodactyle), the other has them even (artiodactyle).

Now, the macrauchenia, from the first relics of it which were found, {110}
was thought to belong, as has been said, to the even-toed division.
Subsequent discoveries, however, seemed to give it an equal claim to rank
amongst the perissodactyle forms. Others again inclined the balance of
probability towards the artiodactyle. Finally, it appears that this very
recently extinct beast presents a highly generalized type of structure,
uniting in one organic form both artiodactyle and perissodactyle
characters, and that in a manner not similarly found in any other known
creature living, or fossil. At the same time the differentiation of
artiodactyle and perissodactyle forms existed as long ago as in the period
of the Eocene ungulata, and that in a marked degree, as has been before
observed.

Again, no armadillo _now living_ presents nearly so remarkable a speciality
of structure as was possessed by the _extinct_ glyptodon. In that singular
animal the spinal column had most of its joints fused together, forming a
rigid cylindrical rod, a modification, as far as yet known, absolutely
peculiar to it.

[Illustration: DENTITION OF THE SABRE-TOOTHED TIGER (MACHAIRODUS).]

In a similar way the _extinct_ machairodus, or sabre-toothed tiger, is
characterized by a more highly differentiated and specially carnivorous
dentition than is shown by any predacious beast of the _present day_. {111}
The specialization is of this kind. The grinding teeth (or molars) of
beasts are divided into premolars and true molars. The premolars are molars
which have deciduous vertical predecessors (or milk teeth), and any which
are in front of such, _i.e._ between such and the canine tooth. The true
molars are those placed behind the molars having deciduous vertical
predecessors. Now, as a dentition becomes more distinctly carnivorous, so
the hindmost molars and the foremost premolars disappear. In the existing
cats this process is carried so far that in the upper jaw only one true
molar is left on each side. In the machairodus there is no upper true molar
at all, while the premolars are reduced to two, there being only these two
teeth above, on each side, behind the canine.

Now, with regard to these instances of early specialization, as also with
regard to the changed estimate of the degrees of affinity between forms, it
is not pretended for a moment that such facts are irreconcilable with
"Natural Selection." Nevertheless, they point in an opposite direction. Of
course not only is it conceivable that certain antique types arrived at a
high degree of specialization and then disappeared; but it is manifest they
did do so. Still the fact of this early degree of excessive specialization
tells to a certain, however small, extent against a progress through
excessively minute steps, whether fortuitous or not; as also does the
distinctness of forms formerly supposed to constitute connecting links.
For, it must not be forgotten, that if species have manifested themselves
generally by gradual and minute modifications, then the absence, not in one
but in _all cases_, of such connecting links, is a phenomenon which remains
to be accounted for.

It appears then that, apart from fortuitous changes, there are certain
difficulties in the way of accepting extremely minute modifications of any
kind, although these difficulties may not be insuperable. Something, at all
events, is to be said in favour of the opinion that sudden and {112}
appreciable changes have from time to time occurred, however they may have
been induced. Marked _races_ have undoubtedly so arisen (some striking
instances having been here recorded), and it is at least conceivable that
such may be the mode of _specific_ manifestation generally, the possible
conditions as to which will be considered in a later chapter. [Page 113]

* * * * *


CHAPTER V.

AS TO SPECIFIC STABILITY.

What is meant by the phrase "specific stability;" such stability to be
expected _a priori_, or else considerable changes at once.--Rapidly
increasing difficulty of intensifying race characters; alleged causes
of this phenomenon; probably an internal cause co-operates.--A certain
definiteness in variations.--Mr. Darwin admits the principle of
specific stability in certain cases of unequal variability.--The
goose.--The peacock.--The guinea fowl.--Exceptional causes of variation
under domestication.--Alleged tendency to
reversion.--Instances.--Sterility of hybrids.--Prepotency of pollen of
same species, but of different race.--Mortality in young gallinaceous
hybrids.--A bar to intermixture exists
somewhere.--Guinea-pigs.--Summary and conclusion.

As was observed in the preceding chapters, arguments may yet be advanced in
favour of the opinion that species are stable (at least in the intervals of
their comparatively sudden successive manifestations); that the organic
world consists, according to Mr. Galton's before-mentioned conception, of
many facetted spheroids, each of which can repose upon any one facet, but,
when too much disturbed, rolls over till it finds repose in stable
equilibrium upon another and distinct facet. Something, it is here
contended, may be urged, in favour of the existence of such facets--of such
intermitting conditions of stable equilibrium.

A view as to the stability of species, in the intervals of change, has been
well expressed in an able article, before quoted from, as follows:[104]--"A
given animal or plant appears to be contained, as it were, within a {114}
sphere of variation: one individual lies near one portion of the surface;
another individual, of the same species, near another part of the surface;
the average animal at the centre. Any individual may produce descendants
varying in any direction, but is more likely to produce descendants varying
towards the centre of the sphere, and the variations in that direction will
be greater in amount than the variations towards the surface." This might
be taken as the representation of the normal condition of species (_i.e._
during the periods of repose of the several facets of the spheroids), on
that view which, as before said, may yet be defended.

Judging the organic world from the inorganic, we might expect, _a priori_,
that each species of the former, like crystallized species, would have an
approximate limit of form, and even of size, and at the same time that the
organic, like the inorganic forms, would present modifications in
correspondence with surrounding conditions; but that these modifications
would be, not minute and insignificant, but definite and appreciable,
equivalent to the shifting of the spheroid on to another facet for support.

Mr. Murphy says,[105] "Crystalline formation is also dependent in a very
remarkable way on the medium in which it takes place." "Beudant has found
that common salt crystallizing from pure water forms cubes, but if the
water contains a little boracic acid, the angles of the cubes are
truncated. And the Rev. E. Craig has found that carbonate of copper,
crystallizing from a solution containing sulphuric acid, forms hexagonal
tubular prisms; but if a little ammonia is added, the form changes to that
of a long rectangular prism, with secondary planes in the angles. If a
little more ammonia is added, several varieties of rhombic octahedra
appear; if a little nitric acid is added, the rectangular prism appears
again. The changes take place not by the addition of new crystals, but by
changing the growth of the original ones." These, however, may be said{115}
to be the same species, after all; but recent researches by Dr. H.
Charlton-Bastian seem to show that modifications in the conditions may
result in the evolution of forms so diverse as to constitute different
organic species.

Mr. Murphy observes[106] that "it is scarcely possible to doubt that the
various forms of fungi which are characteristic of particular situations
are not really distinct species, but that the same germ will develop into
different forms, according to the soil on which it falls;" but it is
possible to interpret the facts differently, and it may be that these are
the manifestations of really different and distinct species, developed
according to the different and distinct circumstances in which each is
placed. Mr. Murphy quotes Dr. Carpenter[107] to the effect that "No
_Puccinia_ but the _Puccinia rosae_ is found upon rose bushes, and this is
seen nowhere else; _Omygena exigua_ is said to be never seen but on the
hoof of a dead horse; and _Isaria felina_ has only been observed upon the
dung of cats, deposited in humid and obscure situations." He adds, "We can
scarcely believe that the air is full of the germs of distinct species of
fungi, of which one never vegetates until it falls on the hoof of a dead
horse, and another till it falls on cat's dung in a damp and dark place."
This is true, but it does not quite follow that they are necessarily the
same species if, as Dr. Bastian seems to show, thoroughly different and
distinct organic forms[108] can be evolved one from another by modifying
the conditions. This observer has brought forward arguments and facts from
which it would appear that such definite, sudden, and considerable
transformations may take place in the lowest organisms. If such is really
the case, we might expect, _a priori_, to find in the highest organisms a
tendency (much more impeded and rare in its manifestations) to {116}
similarly appreciable and sudden changes, under certain stimuli; but a
tendency to continued stability, under normal and ordinary conditions. The
proposition that species have, under ordinary circumstances, a definite
limit to their variability, is largely supported by facts brought forward
by the zealous industry of Mr. Darwin himself. It is unquestionable that
the degrees of variation which have been arrived at in domestic animals
have been obtained more or less readily in a moderate amount of time, but
that further development in certain desired directions is in some a matter
of extreme difficulty, and in others appears to be all but, if not quite,
an impossibility. It is also unquestionable that the degree of divergence
which has been attained in one domestic species is no criterion of the
amount of divergence which has been attained in another. It is contended on
the other side that we have no evidence of any limits to variation other
than those imposed by physical conditions, such, _e.g._, as those which
determine the greatest degree of speed possible to any animal (of a given
size) moving over the earth's surface; also it is said that the differences
in degree of change shown by different domestic animals depend in great
measure upon the abundance or scarcity of individuals subjected to man's
selection, together with the varying direction and amount of his attention
in different cases; finally, it is said that the changes found in nature
are within the limits to which the variation of domestic animals
extends,--it being the case that when changes of a certain amount have
occurred to a species under nature, it becomes _another species_, or
sometimes _two or more other species_ by divergent variations, each of
these species being able again to vary and diverge in any useful direction.

But the fact of the rapidly increasing difficulty found in producing by
ever such careful selection, any further extreme in some charge already
carried very far (such as the tail of the "fan-tailed pigeon" or the crop
of the "pouter"), is certainly, so far as it goes, on the side of the {117}
existence of definite limits to variability. It is asserted in reply, that
physiological conditions of health and life may bar any such further
development. Thus, Mr. Wallace says[109] of these developments: "Variation
seems to have reached its limits in these birds. But so it has in nature.
The fantail has not only more tail-feathers than any of the three hundred
and forty existing species of pigeons, but more than any of the eight
thousand known species of birds. There is, of course, some limit to the
number of feathers of which a tail useful for flight can consist, and in
the fantail we have probably reached that limit. Many birds have the
oesophagus or the skin of the neck more or less dilatable, but in no known
bird is it so dilatable as in the pouter pigeon. Here again the possible
limit, compatible with a healthy existence, has probably been reached. In
like manner, the differences in the size and form of the beak in the
various breeds of the domestic pigeon, is greater than that between the
extreme forms of beak in the various genera and sub-families of the whole
pigeon tribe. From these facts, and many others of the same nature, we may
fairly infer, that if rigid selection were applied to any organ, we could
in a comparatively short time produce a much greater amount of change than
that which occurs between species and species in a state of nature, since
the differences which we do produce are often comparable with those which
exist between distinct genera or distinct families."

But in a domestic bird like the fantail where Natural Selection does not
come into play, the tail-feathers could hardly be limited by "utility for
flight," yet two more tail-feathers could certainly exist in a fancy breed
if "utility for flight" were the only obstacle. It seems probable that the
real barrier is an _internal_ one in the nature of the organism, and the
existence of such is just what is contended for in this chapter. As to{118}
the differences between domestic races being greater than those between
species or even genera, that is not enough for the argument. For upon the
theory of "Natural Selection" all birds have a common origin, from which
they diverged by infinitesimal changes, so that we ought to meet with
sufficient changes to warrant the belief that a hornbill could be produced
from a humming-bird, proportionate time being allowed.

But not only does it appear that there are barriers which oppose change in
certain directions, but that there are positive tendencies to development
along certain special lines. In a bird which has been kept and studied like
the pigeon, it is difficult to believe that any remarkable spontaneous
variations would pass unnoticed by breeders, or that they would fail to be
attended to and developed by some one fancier or other. On the hypothesis
of _indefinite_ variability, it is then hard to say why pigeons with bills
like toucans, or with certain feathers lengthened like those of trogans, or
those of birds of paradise, have never been produced. This, however, is a
question which may be settled by experiment. Let a pigeon be bred with a
bill like a toucan's, and with the two middle tail-feathers lengthened like
those of the king bird of paradise, or even let individuals be produced
which exhibit any marked tendency of the kind, and indefinite variability
shall be at once conceded.

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