Goldwin Smith - "Specimens of Greek Tragedy"

George MacDonald - "Adela Cathcart, Vol. 1"

William Shakespeare - "Der Kaufmann von Venedig"

Translated from the German by Sophie A. Miller and Agnes M. Dunne - "After Long Years and Other Stories"

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.

Form and Function

E >> E. S. (Edward Stuart) Russell >> Form and Function




Sedgwick expressed the same thing from the morphological point of view
when he wrote, with reference to the ancestral significance of the
blastopore:--"If there is anything in the theory of evolution, every
change in the embryo must have had a counterpart in the history of the
race, and it is our business as morphologists to find it out" (p. 49,
1884).

By the evolution-theory the problems of form were linked indissolubly
with the problem of heredity. Unity of plan could no longer be explained
idealistically as the manifestation of Divine archetypal ideas; it had a
real historical basis, and was due to inheritance from a common
ancestor. The evolution-theory gave meaning and intelligibility to the
transcendental conception of the unity of plan; in particular it
supplied a simple and satisfying explanation of those puzzling vestigial
organs, whose existence was such a stumbling-block to the teleologists.
It enabled the biogenetic law to be substituted for the laws of
Meckel-Serres and von Baer, as being in some measure a combination and
interpretation of both.

Where the concept of evolution proved itself particularly useful was in
the interpretation of structures which were not immediately conditioned
by adaptation to present requirements, such as, for instance, the
arrangement of gill-slits and aortic arches in the foetus of land
Vertebrates. Such "heritage characters" could only be explained on the
hypothesis that they had once had functional or adaptational meaning.
Why, for instance, should the blastopore so often appear as a long slit,
closing by concrescence, unless this had been the original method of its
formation in remote Coelenterate ancestors?

The point hardly requires elaboration, since it has become an integral
part of all our thinking on biological problems. It may be as well,
however, for the sake of continuity, to give one or two examples of the
historical interpretation of animal structures. The first may
conveniently be the phylogenetic interpretation of the contrast between
"membrane" and "cartilage" bones.

In his _Grundzuege_ of 1870, Gegenbaur made the suggestion that the
investing or membrane bones were derived phylogenetically from
integumentary ossifications, and this was worked out in detail a few
years later by O. Hertwig.[458]

Many years before, several observers--J. Mueller, Williamson, and
Steenstrup--had been struck with the resemblance existing between the
placoid scales and the teeth of Elasmobranch fishes. Hertwig followed up
this clue, and came to the conclusion not only that placoid scales and
teeth were strictly homologous, but also that all membrane bones were
derived phylogenetically from ossifications present in the skin or in
the mucous membrane of the mouth, just as cartilage bones were derived
from the cartilaginous skeletons of the primitive Vertebrates. In some
cases this manner of derivation could even be observed in ontogeny, as
Reichert had seen in the Newt, where certain bones in the roof of the
mouth are actually formed by the concrescence of little teeth, (_supra_,
p. 163). Hertwig considered that the following bones were originally
formed by coalescence of teeth--parasphenoid, vomer, palatine,
pterygoid, the tooth-bearing part of the pre-maxillary, the maxillary,
the dentary and certain bones of the hyo-mandibular skeleton of
Teleosts. All the investing bones (_Deckknochen_) of the skull were of
common origin, and could be traced back to integumentary skeletal
plates, which in the ancestral fish formed a dense carapace.

These conclusions were accepted by Koelliker himself, who wrote in his
_Entwickelungsgeschichte_ (1879)--"The distinction between the primary
or primordial, and the investing or secondary bones is from the
morphological standpoint sharp and definite. The former are
ossifications of the (cartilaginous) primordial skeleton, the latter are
formed outside this skeleton, and are probably all ossifications of the
skin or the mucous membrane" (p. 464).

Gegenbaur[459] consistently upheld the phylogenetic derivation of
investing bones from dermal ossifications, and even went further and
derived substitutionary bones as well from the integument, thus
establishing a direct comparison between the skeletal formations of
Vertebrates and Invertebrates. Investing bones were actual integumentary
ossifications which had gradually sunk beneath the skin to become part
of the internal skeleton; substitutionary bones were produced by cells
(osteoblasts) which were ultimately derived from the integument.[460]

A further instance of the historical interpretation of animal structure,
taken from quite a different field, is afforded by the speculations of
Dollo[461] on the ancestral history of the Marsupials. In a brilliant
paper of 1880[462] Huxley made the suggestion that the ancestors of
Marsupials were arboreal forms. "I think it probable," he wrote, "from
the character of the pes, that the primitive forms, whence the existing
Marsupialia have been derived, were arboreal animals; and it is not
difficult, I conceive, to see that, with such habits, it may have been
highly advantageous to an animal to get rid of its young from the
interior of its body at as early a period of development as possible,
and to supply it with nourishment during the later periods through the
lacteal glands, rather than through an imperfect form of placenta" (p.
655). Dollo followed up this suggestion, which had in the meantime been
strengthened by Hill's discovery of a true allantoic placenta in
_Perameles_, by demonstrating in the foot of present-day Marsupials
certain features which could only be interpreted as inherited from a
time when the ancestors of Marsupials were tree-living animals. These
were the occurrence of an opposable big toe (when this was present at
all), the great development of the fourth toe, the reduction and partial
syndactylism of the second and third toes, and in some cases the
regression of the nails. These characters were shown to be typical of
arboreal Vertebrates, and their occurrence in forms not arboreal
indicated that these were descended from tree-living ancestors. Traces
of an arboreal ancestry could be demonstrated even in the marsupial mole
_Notoryctes_.

These are only two examples out of hundreds that might be given. Present
day structure was interpreted in the light of past history; the common
element in organic form was seen to be due to common descent; the
existence of vestigial and non-functional organs was no longer a riddle.

There was even a tendency to concentrate attention upon the historical
side of structure, upon what the animal passively inherited rather than
upon what it personally achieved. Homologies were considered more
interesting than analogies, vestigial organs more interesting than
foetal and larval adaptations. Convergence was anathema. The dead-weight
of the past was appreciated at its full and more than its full value;
and the essential vital activity of the living thing, so clearly shown
in development and regeneration, was ignored or forgotten.

But evolutionary morphology for all practical purposes was a development
of pure or idealistic morphology, and was powerless to bring to fruit
the new conception with which evolution-theory had enriched it. The
reason is not far to seek. Pure morphology is essentially a science of
comparison which seeks to disentangle the unity hidden beneath the
diversity of organic form. It is not immediately concerned with the
causes of organic diversity--that is rather the task of the sciences of
the individual, heredity and development. To take an example--the
recapitulation theory may legitimately be used as a law of pure
morphology, as stating the abstract relation of ontogeny to phylogeny,
and the probable line of descent of any organism may be deduced from it,
as a mere matter of the ideal derivation of one form from another; but
an explanation of the reason for the recapitulation of ancestral history
during development can clearly not be given by pure morphology unaided.
From the fact that the common starfish shows in the course of its
development distinct traces of a stalk[463] it is possible to infer,
taking other evidence also into consideration, that the ancestors of the
starfish were at one stage of their existence stalked and sessile
organisms. But this leaves unanswered the question as to how and why the
starfish does still repeat after so many millions of years part of the
organisation of one of its remote ancestors. Why is this feature
retained, and by what means has it been conserved through countless
generations? It is clear that the answer can be given only by a science
of the causes of the production and retention of form, by a causal
morphology, based upon a study of heredity and development.

From the point of view of the pure morphologist the recapitulation
theory is an instrument of research enabling him to reconstruct probable
lines of descent; from the standpoint of the student of development and
heredity the fact of recapitulation is a difficult problem whose
solution would perhaps give the key to a true understanding of the real
nature of heredity.

To make full use of the conception of the organism as an historical
being it is necessary then to understand the causal nexus between
ontogeny and phylogeny.

We shall see in the next chapter that the transformation of morphology
from a comparative to a causal science did take place towards the end of
the century, and that some progress was made towards an understanding of
the relation between individual development and ancestral history,
particularly by Roux and Samuel Butler, working with the fruitful
Lamarckian conception of the transforming power of function.

[456] The importance of convergence came to be realised
after the vogue of phylogenetic speculation had
passed--see Friedmann, _Die Konvergenz der Organismen_,
Berlin, 1904, and A. Willey, _Convergence in Evolution_,
London, 1911. Also L. Vialleton, _Elements de
morphologie des Vertebres_, Paris, 1912.

[457] From this point of view there is a very profound
analogy between artificial and natural selection. Upon
the theory of natural selection organisms are lifeless
constructs which are mechanically perfected by external
agency, just as machines are improved by a process of
conscious selection of the most successful among a
number of competing models. (_Cf._ passage quoted below,
on p. 308.)

[458] _Arch. f. mikr. Anat._, xi. (suppl.), 1874; _Morph.
Jahrb._, ii., 1876, v. 1879, and vii., 1882.

[459] _Vergleich. Anat. d. Wirbelthiere_, i., pp. 200-1,
1898.

[460] For a full historical account of work on membrane
and cartilage bones (as well as on the theory of the
skull) see E. Gaupp, "Altere und neuere Arbeiten ueber
den Wirbelthierschaedel," _Ergeb. Anat. Entw._, x., 1901,
and "Die Entwickelung des Kopfskelettes," in Hertwig's
"_Handbuch vergl. exper. Entwickelungslehre d.
Wirbelthiere_," iii., 2, pp. 573-874, 1905.

[461] "Les Ancetres des Marsupiaux etaient-ils
arboricoles?" _Trav. Stat. zool. Wimereux_, vii., pp.
188-203, pls. xi.-xii., 1899. See also Bensley, _Trans.
Linn. Soc._ (2) ix., pp. 83-214, 1903.

[462] _Proc. Zool. Soc._, pp. 649-62, 1880. _Sci. Mem._,
iv., pp. 457-72.

[463] J. F. Gemmill, _Phil. Trans. B_, ccv., p. 255, 1914.




CHAPTER XVIII

THE BEGINNINGS OF CAUSAL MORPHOLOGY


Until well into the 'eighties animal morphology remained a purely
descriptive science, content to state and summarise the relations
between the coexistent and successive form-states of the same and of
different animals. No serious attempt had been made to discover the
causes which led to the production of form in the individual and in the
race.

It is true that evolution-theory had offered a simple solution of the
great problem of the unity in diversity of animal forms, but this
solution was formal merely, and went little beyond that abstract
deduction of more complex from simpler forms, which had been the main
operation of pre-evolutionary morphology. Little was known of the actual
causes of ontogeny, and nothing at all of the causes of phylogeny; it
was, for instance, mere rhetoric on Haeckel's part to proclaim that
phylogeny was the mechanical cause of ontogeny.

Animal physiology, on its side, had developed in complete isolation from
morphology into a science of the functioning of the adult and finished
animal, considered as a more or less stable physico-chemical mechanism.
Since the days of Ludwig, Claude Bernard and E. du Bois Reymond, the
physiologists' chief care had been to analyse vital activities into
their component physical and chemical processes, and to trace out the
interchange of matter and energy between the organism and its
environment. Physiologists had left untouched, perhaps wisely, the much
more difficult problem of the causes of the development of form. For all
practical purposes they took the animal-machine as given, and did not
trouble about its mode of origin. They held indeed that form-production
was due to a complex of physico-chemical causes, which they hoped some
day to unravel;[464] but this future physiology of development remained
quite embryonic.

Physiology then had not really come into contact with the problems of
form, and it could give the morphologist no direct help when he turned
to investigate the causes of form-production. It had, however, a
determining influence upon the methods of those who first broke ground
in this No Man's Land between morphology proper and physiology. But it
is significant that it was a morphologist and not a physiologist that
did the first spade-work.

The pioneer in this field, both as investigator and as thinker, was W.
Roux, who sketched in the 'eighties the main outlines of a new science
of causal morphology, to which he gave the name of
_Entwicklungsmechanik_. The choice of name was deliberate, and the word
implied, first, that the new science was essentially an investigation of
the development of form, not of the mode of action of a formed
mechanism, and second, that the methods to be adopted were
mechanistic.[465]

Though Roux was the only begetter of the science of
_Entwicklungsmechanik_, he was, of course, not the first to investigate
experimentally the formative processes of animal life. Study of
regeneration dates back to Trembley (1740-44), Reaumur (1742), Bonnet
(1745), and Spallanzani (1768-82),[466] and in the years preceding Roux's
activity good work was done by Philipeaux. A beginning had been made
with experimental teratology by E. Geoffroy St Hilaire and others, and
the work of C. Dareste[467] remains classical. Back in the 18th century,
some of John Hunter's experiments had a bearing upon the problems of
form; his work on transplantation was followed up in the 19th century by
Flourens, P. Bert, Ollier and many others. In founding in 1872 the
_Archives de Zoologie experimentale et generale_ H. de Lacaze-Duthiers
put forward in his introduction a powerful plea for the use of the
experimental method in zoology.

In some ways more directly connected with _Entwicklungsmechanik_ was
His's attempt in 1874[468] to explain on mechanical principles the
formation of certain of the embryonic organs by the bendings and
foldings of tubes or plates of cells. "His compared the various layers
of the chick embryo to elastic plates and tubes; out of these he
suggested that some of the principal organs might be moulded by mere
local inequalities of growth--the ventricles of the brain, for instance,
the alimentary canal, the heart--and he further succeeded in imitating
the formation of these organs by folding, pinching, and cutting
india-rubber tubes and plates in various ways."[469]

But Roux was undoubtedly the first to make a systematic survey of the
problems to be solved and to work out an organised method of attack. His
earliest work deals with the important problem of functional
adaptation--its importance to the organism, and its possible mechanistic
explanation. The first paper[470] was a study of the branching and
distribution of the arteries in the human body (1878), and a second
paper on the same subject followed in 1879.[471]

In these papers Roux showed how the development of the blood-vascular
system was largely determined by direct adaptation to functional
requirements, and he inferred the existence in the vascular tissues of
certain vital properties, in virtue of which the functional adaptation
of the blood-vessels came about. Thus the intima or inner lining must
possess the faculty of so reacting to the friction set up by the
blood-current as to oppose the least possible resistance to its flow;
the muscular coats must react to increased pressure by growing thicker,
and so on.

These papers were followed in 1881 by his well-known book, _Der Kampf
der Theile im Organismus_, which contained the working-out of his
mechanistic explanation of functional adaptation, and most of the
elements of his general "causal-analytical" theory of form production.
The significance of the book was popularly considered at the time to lie
in its supposed application of the selection idea to the explanation of
the internal adaptedness of animal structure--in the theory of "cellular
selection," and the book owed its success to its fitting in so well with
the prevalent Darwinism of the day. But its real importance, as a big
step towards causal morphology, was naturally not so fully appreciated.

During the next few years Roux continued his studies on functional
adaptation,[472] and at the same time made a new departure by
inaugurating, almost contemporaneously with the physiologist Pflueger,
the study of experimental embryology. Isolated observations had
previously been made upon the development of single blastomeres or parts
of blastulae, by Haeckel and Chun for instance,[473] but Roux[474] and
Pflueger[475] were the first to investigate the subject systematically,
choosing for their work the egg of the frog.[476] Roux continued for many
years to follow up this line of work.[477]

In 1890 he drew up a programme and manifesto[478] of
_Entwicklungsmechanik_ as "an anatomical science of the future," and in
1895 he founded the famous _Archiv fuer Entwicklungsmechanik_,[479]
publishing in the same year the two large volumes of his collected
papers,[480] of which the first volume dealt with functional adaptation,
the second with experimental embryology.

His subsequent work includes several important general papers;[481]
besides a number of special memoirs dealing with the factors of
development, and with his original subject, functional adaptation.[482]

In our sketch of his views we shall have occasion to refer particularly
to his publications of 1881, 1895 (the _Einleitung_), 1902, 1905, and
1910.

Although Roux's biological philosophy is out-and-out mechanistic, he yet
recognises the difficulty, even the impossibility, of straightway
reducing development to the physico-chemical level. He tries to steer a
course midway between the simplicist conceptions of the materialists and
the "metaphysics" of the neo-vitalist school, which the experimental
study of development and regeneration soon brought into being. In 1895
he writes:--"The too simple mechanistic conception on the one hand, and
the metaphysical conception on the other represent the Scylla and
Charybdis, between which to sail is indeed difficult, and so far by few
satisfactorily accomplished; it cannot be denied that with the increase
of knowledge the seduction of the second has lately notably increased"
(p. 23).

The _via media_ adopted by Roux is the analysis of development, not
directly into simple physico-chemical processes, but into more complex
organic processes dependent upon the fundamental properties of living
matter. The aim of _Entwicklungsmechanik_ is defined by Roux to be the
reduction of developmental events to the fewest and simplest
_Wirkungsweisen_, or causal processes.[483] Two classes of causal
processes may be distinguished, as "complex components" and "simple
components" of development. The latter are directly explicable by the
laws of physics and chemistry; the former, while in essence
physico-chemical, are yet so very complicated that they cannot at
present be reduced to physico-chemical terms. The ultimate aim of
_Entwicklungsmechanik_ is to reduce development to its "simple
components," but its main task at the present day and for many years to
come is the analysis of development into its "complex components."

These complex components must be accepted as having much of the validity
of physical and chemical laws. They are mysterious in the sense that
they cannot yet be explained mechanistically, but they are constant in
their action, and under the same conditions produce always the same
effect--hence they may be made the subject of strictly scientific study.
They represent biological generalisations, in their way of equal
validity with the generalisations of physics and chemistry.

The principal "complex components" which Roux recognises are somewhat as
follows:--First come the elementary cell-functions of assimilation and
dissimilation, growth, reproduction and heredity, movement and
self-division (as a special co-ordination of cell-movements). Then at a
somewhat higher level, self-differentiation, and the trophic reaction to
functional stimuli. Components of even greater complexity may also be
distinguished, as, for instance, the biogenetic law. The various
tropisms exhibited in development may be regarded as "directive" complex
components. There must be added, not as being itself a component, but
rather as a mode or peculiar property of all functioning, the
omnipresent faculty of self-regulation.

It will be noticed that Roux's "complex components" are simply the
general properties or functions of organised matter.

Expressing Roux's thought in another way, we might say that life can
only be defined functionally, _i.e._, by an enumeration of the "complex
components" or elementary functions which all living beings manifest,
even down to the very simplest. "Living beings," writes Roux, "can at
present be defined with any approach to completeness only functionally,
that is to say, through characterisation of their activities, for we
have an adequate acquaintance with their functions in a general way,
though our knowledge of particulars is by no means complete" (p. 105,
1905). Defined in the most general and abstract way, living things are
material objects which persist in spite of their metabolism, and, by
reason of their power of self-regulation, in spite also of the changes
of the environment. This is the "functional minimum-definition of life"
(pp. 106-7, 1905).

We may now go on to consider the relation of function to form throughout
the course of development. Roux distinguishes in all development two
periods, in the first of which the organ is formed prior to and
independent of its function, while in the second the differentiation and
growth of the organ are dependent on its functioning. Latterly (1906 and
1910) Roux has distinguished three periods, counting as the second the
transition period when form is partly self-determined, partly determined
by functioning. As this conception of Roux's is of the greatest
importance we shall follow it out in some detail.

The idea was first elaborated in the _Kampf der Theile_ (1881), where he
wrote:--"There must be distinguished in the life of all the parts two
periods, an embryonic in the broad sense, during which the parts
develop, differentiate and grow of themselves, and a period of completer
development, during which growth, and in many cases also the balance of
assimilation over dissimilation, can come about only under the influence
of stimuli" (p. 180). There is thus a period of self-differentiation in
which the organs are roughly formed in anticipation of functioning, and
a period of functional development in which the organs are perfected
through functioning and only through functioning. The two periods cannot
be sharply separated from one another, nor does the transition from the
one to the other occur at the same time in the different tissues and
organs.

The conception is more fully expressed in 1905 as follows:--"This
separation (of development into two periods) is intended only as a first
beginning. The first period I called the embryonic period [Greek: kat'
exochen] or the period of organ-rudiments. It includes the 'directly
inherited' structures, _i.e._, the structures which are directly
predetermined in the structure of the germ-plasm, as, for instance, the
first differentiation of the germ, segmentation, the formation of the
germ-layers and the organ-rudiments, as well as the next stage of
'further differentiation,' and of _independent_ growth and maintenance,
that is, of growth and maintenance which take place without the
functioning of the organs.

"This is accordingly the period of direct fashioning through the
activity of the formative mechanism implicit in the germ-plasm, also the
period of the self-conservation of the formed parts without active
functioning.

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