James Hay, Jr. - "The Winning Clue"

William L. Stidger - "Giant Hours With Poet Preachers"

Gotthold Ephraim Lessing - "Fabeln und Erzaehlungen"

Henry Beam Piper - "Oomphel in the Sky"

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.

The Botanic Garden

E >> Erasmus Darwin >> The Botanic Garden




Plants are said by many writers to grow much faster in the night than in
the day; as is particularly observable in seedlings at their rising out
of the ground. This probably is a consequence of their sleep rather than
of the absence of light; and in this I suppose they also resemble animal
bodies.




NOTE XXXV.--VEGETABLE PLACENTATION.


_While in bright veins the silvery sap ascends.

CANTO IV. l. 419.


As buds are the viviparous offspring of vegetables, it becomes necessary
that they should be furnished with placental vessels for their
nourishment, till they acquire lungs or leaves for the purpose of
elaborating the common juices of the earth into nutriment. These vessels
exist in bulbs and in seeds, and supply the young plant with a sweet
juice till it acquires leaves, as is seen in converting barley into
malt, and appears from the sweet taste of onions and potatoes, when they
begin to grow.

The placental vessels belonging to the buds of trees are placed about
the roots of most, as the vine; so many roots are furnished with sweet
or mealy matter as fern-root, bryony, carrot, turnip, potatoe, or in the
alburnum or sap-wood as in those trees which produce manna, which is
deposited about the month of August, or in the joints of sugar cane, and
grasses; early in the spring the absorbent mouths of these vessels drink
up moisture from the earth, with a saccharine matter lodged for that
purpose during the preceding autumn, and push this nutritive fluid up
the vessels of the alburnum to every individual bud, as is evinced by
the experiments of Dr. Hales, and of Mr. Walker in the Edinburgh
Philosophical Transact. The former observed that the sap from the stump
of a vine, which he had cut off in the beginning of April, arose twenty-
one feet high in tubes affixed to it for that purpose, but in a few
weeks it ceased to bleed at all, and Dr. Walker marked the progress of
the ascending sap, and found likewise that as soon as the leaves became
expanded the sap ceased to rise; the ascending juice of some trees is so
copious and so sweet during the sap-season that it is used to make wine,
as the birch, betula, and sycamore, acer pseudo-platinus, and
particularly the palm.

During this ascent of the sap-juice each individual leaf-bud expands its
new leaves, and shoots down new roots, covering by their intertexture
the old bark with a new one; and as soon as these new roots (or bark)
are capable of absorbing sufficient juices from the earth for the
support of each bud, and the new leaves are capable of performing their
office of exposing these juices to the influence of the air; the
placental vessels cease to act, coalesce, and are transformed from sap-
wood, or alburnum, into inert wood; serving only for the support of the
new tree, which grows over them.

Thus from the pith of the new bud of the horse-chesnut five vessels pass
out through the circle of the placental vessels above described, and
carry with them a minuter circle of those vessels; these five bundles of
vessels unite after their exit, and form the footstalk or petiole of the
new five-fingered leaf, to be spoken of hereafter. This structure is
well seen by cutting off a leaf of the horse-chesnut (Aesculus
Hippocastanum) in September before it falls, as the buds of this tree
are so large that the flower may be seen in them with the naked eye.

After a time, perhaps about midsummer, another bundle of vessels passes
from the pith through the alburnum or sap-vessels in the bosom of each
leaf, and unites by the new bark with the leaf, which becomes either a
flower-bud or a leaf-bud to be expanded in the ensuing spring, for which
purpose an apparatus of placental vessels are produced with proper
nutriment during the progress of the summer and autumn, and thus the
vegetable becomes annually increased, ten thousand buds often existing
on one tree, according to the estimate of Linneus. Phil. Bot.

The vascular connection of vegetable buds with the leaves in whose
bosoms they are formed is confirmed by the following experiment, (Oct.
20, 1781.) On the extremity of a young bud of the Mimosa (sensitive
plant) a small drop of acid of vitriol was put by means of a pen, and,
after a few seconds, the leaf in whose axilla it dwelt closed and opened
no more, though the drop of vitriolic acid was so small as apparently
only to injure the summit of the bud. Does not this seem to shew that
the leaf and its bud have connecting vessels though they arise at
different times and from different parts of the medulla or pith? And, as
it exists previously to it, that the leaf is the parent of the bud?

This placentation of vegetable buds is clearly evinced from the
sweetness of the rising sap, and from its ceasing to rise as soon as the
leaves are expanded, and thus compleats the analogy between buds and
bulbs. Nor need we wonder at the length of the umbilical cords of buds
since that must correspond with their situation on the tree, in the same
manner as their lymphatics and arteries are proportionally elongated.

It does not appear probable that any umbilical artery attends these
placental absorbents, since, as there seems to be no system of veins in
vegetables to bring back the blood from the extremities of their
arteries, (except their pulmonary veins,) there could not be any
vegetable fluids to be returned to their placenta, which in vegetables
seems to be simply an organ for nutrition, whereas the placenta of the
animal foetus seems likewise to serve as a respiratory organ like the
gills of fishes.




NOTE XXXVI--VEGETABLE CIRCULATION.


_And refluent blood in milky eddies bends._

CANTO IV. l. 420.


The individuality of vegetable buds was spoken of before, and is
confirmed by the method of raising all kinds of trees by Mr. Barnes.
(Method of propagating Fruit Trees. 1759. Lond. Baldwin.) He cut a
branch into as many pieces as there were buds or leaves upon it, and
wiping the two wounded ends dry he quickly applied to each a cement,
previously warmed a little, which consisted principally of pitch, and
planted them in the earth. The use of this cement I suppose to consist
in its preventing the bud from bleeding to death, though the author
ascribes it to its antisceptic quality.

These buds of plants, which are thus each an individual vegetable, in
many circumstances resemble individual animals, but as animal bodies are
detached from the earth, and move from place to place in search of food,
and take that food at considerable intervals of time, and prepare it for
their nourishiment within their own bodies after it is taken, it is
evident they must require many organs and powers which are not necessary
to a stationary bud. As vegetables are immoveably fixed to the soil from
whence they draw their nourishment ready prepared, and this uniformly
not at returning intervals, it follows that in examining their anatome
we are not to look for muscles of locomotion, as arms and legs; nor for
organs to receive and prepare their nourishment, as a stomach and
bowels; nor for a reservoir for it after it is prepared, as a general
system of veins, which in locomotive animals contains and returns the
superfluous blood which is left after the various organs of secretion
have been supplied, by which contrivance they are enabled to live a long
time without new supplies of food.

The parts which we may expert to find in the anatome of vegetables
correspondent to those in the animal economy are, 1. A system of
absorbent vessels to imbibe the moisture of the earth similar to the
lacteal vessels, as in the roots of plants; and another system of
absorbents similar to the lymphatics of animal bodies, opening its
mouths on the internal cells and external surfaces of vegetables; and a
third system of absorbent vessels correspondent with those of the
placentation of the animal foetus. 2. A pulmonary system correspondent
to the lungs or gills of quadrupeds and fish, by which the fluid
absorbed by the lacteals and lymphatics may be exposed to the influence
of the air, this is done by the green leaves of plants, those in the air
resembling lungs, and those in the water resembling gills; and by the
petals of flowers. 3. Arterial systems to convey the fluid thus
elaborated to the various glands of the vegetable for the purposes of
its growth, nutrition, and various secretions. 4. The various glands
which separate from the vegetable blood the honey, wax, gum, resin,
starch, sugar, essential oil, &c. 5. The organs adapted for their
propagation or reproduction. 6. Muscles to perform several motions of
their parts.

I. The existence of that branch of the absorbent vessels of vegetables
which resembles the lacteals of animal bodies, and imbibes their
nutriment from the moist earth, is evinced by their growth so long as
moisture is applied to their roots, and their quickly withering when it
is withdrawn.

Besides these absorbents in the roots of plants there are others which
open their mouths on the external surfaces of the bark and leaves, and
on the internal surfaces of all the cells, and between the bark and the
alburnum or sap-wood; the existence of these is shewn, because a leaf
plucked off and laid with its under side on water will not wither so
soon as if left in the dry air,--the same if the bark alone of a branch
which is separated from a tree be kept moist with water,--and lastly, by
moistening the alburnum or sap-wood alone of a branch detached from a
tree it will not so soon wither as if left in the dry air. By the
following experiment these vessels were agreeably visible by a common
magnifying glass, I placed in the summer of 1781 the footstalks of some
large fig-leaves about an inch deep in a decoction of madder, (rubia
tinctorum,) and others in a decoction of logwood, (haematoxylum
campechense,) along with some sprigs cut off from a plant of picris,
these plants were chosen because their blood is white, after some hours,
and on the next day, on taking out either of these and cutting off from
its bottom about a quarter of an inch of the stalk an internal circle of
red points appeared, which were the ends of absorbent vessels coloured
red with the decoction, while an external ring of arteries was seen to
bleed out hastily a milky juice, and at once evinced both the absorbent
and arterial system. These absorbent vessels have been called by Grew,
and Malphigi, and some other philosophers, bronchi, and erroneously
supposed to be air-vessels. It is probable that these vessels, when cut
through, may effuse their fluids, and receive air, their sides being too
stiff to collapse; since dry wood emits air-bubles in the exhausted
receiver in the same manner as moist wood.

The structure of these vegetable absorbents consists of a spiral line,
and not of a vessel interrupted with valves like the animal lymphatics,
since on breaking almost any tender leaf and drawing out some of the
fibres which adhere longest this spiral structure becomes visible even
to the naked eye, and distinctly so by the use of a common lens. See
Grew, Plate 51.

In such a structure it is easy to conceive how a vermicular or
peristaltic motion of the vessel beginning at the lowest part of it,
each spiral ring successively contracting itself till it fills up the
tube, must forcibly push forwards its contents, as from the roots of
vines in the bleeding season; and if this vermicular motion should begin
at the upper end of the vessel it is as easy to see how it must carry
its contained fluid in a contrary direction. The retrograde motion of
the vegetable absorbent vessels is shewn by cutting a forked branch from
a tree, and immersing a part of one of the forks in water, which will
for many days prevent the other from withering; or it is shewn by
planting a willow branch with the wrong end upwards. This structure in
some degree obtains in the esophagus or throat of cows, who by similar
means convey their food first downwards and afterward upwards by a
retrograde motion of the annular muscles or cartilages for the purpose
of a second mastication of it.

II. The fluids thus drank up by the vegetable absorbent vessels from the
earth, or from the atmosphere, or from their own cells and interfaces,
are carried to the foot-stalk of every leaf, where the absorbents
belonging to each leaf unite into branches, forming so many pulmonary
arteries, and are thence dispersed to the extremities of the leaf, as
may be seen in cutting away slice after slice the footstalk of a horse-
chesnut in September before the leaf falls. There is then a compleat
circulation in the leaf; a pulmonary vein receiving the blood from the
extremities of each artery on the upper side of the leaf, and joining
again in the footstalk of the leaf these veins produce so many arteries,
or aortas, which disperse the new blood over the new bark, elongating
its vessels, or producing its secretions; but as a reservoir of blood
could not be wanted by a vegetable bud which takes in its nutriment at
all times, I imagine there is no venous system, no veins properly so
called, which receive the blood which was to spare, and return it into
the pulmonary or arterial system.

The want of a system of veins was countenanced by the following
experiment; I cut off several stems of tall spurge, (Euphorbia
helioscopia) in autumn, about the centre of the plant, and observed
tenfold the quantity of milky juice ooze from the upper than from the
lower extremity, which could hardly have happened if there had been a
venous system of vessels to return the blood from the roots to the
leaves.

Thus the vegetable circulation, complete in the lungs, but probably in
the other part of the system deficient in respect to a system of
returning veins, is carried forwards without a heart, like the
circulation through the livers of animals where the blood brought from
the intestines and mesentery by one vein is dispersed through the liver
by the vena portarum, which assumes the office of an artery. See Note
XXXVII.

At the same time so minute are the vessels in the intertexture of the
barks of plants, which belong to each individual bud, that a general
circulation may possibly exist, though we have not yet been able to
discover the venous part of it.

There is however another part of the circulation of vegetable juices
visible to the naked eye, and that is in the corol or petals of flowers,
in which a part of the blood of the plant is exposed to the influence of
the air and light in the same manner as in the foliage, as will be
mentioned more at large in Notes XXXVII and XXXIX.

These circulations of their respective fluids seem to be carried on in
the vessels of plants precisely as in animal bodies by their
irritability to the stimulus of their adapted fluids, and not by any
mechanical or chemical attraction, for their absorbent vessels propel
the juice upwards, which they drink up from the earth, with great
violence; I suppose with much greater than is exerted by the lacteals of
animals, probably owing to the greater minuteness of these vessels in
vegetables and the greater rigidity of their coats. Dr. Hales in the
spring season cut off a vine near the ground, and by fixing tubes on the
remaining stump of it, found the sap to rise twenty-one feet in the tube
by the propulsive power of these absorbents of the roots of it. Veget.
Stat. p. 102. Such a power can not be produced by capillary attraction,
as that could only raise a fluid nearly to the upper edge of the
attracting cylinder, but not enable it to flow over that edge, and much
less to rise 21 feet above it. What then can this power be owing to?
Doubtless to the living activity of the absorbent vessels, and to their
increased vivacity from the influence of the warmth of the spring
succeeding the winter's cold, and their thence greater susceptibility to
irritation from the juices which they absorb, resembling in all
circumstances the action of the living vessels of animals.




NOTE XXXVII--VEGETABLE RESPIRATION.

_While spread in air the leaves respiring play._

CANTO IV. l. 421.


I. There have been various opinions concerning the use of the leaves of
plants in the vegetable oeconomy. Some have contended that they are
perspiratory organs; this does not seem probable from an experiment of
Dr. Hales, Veg. Stat. p. 30. He found by cutting off branches of trees
with apples on them, and taking off the leaves, that an apple exhaled
about as much as two leaves, the surfaces of which were nearly equal to
the apple; whence it would appear that apples have as good a claim to be
termed perspiratory organs as leaves. Others have believed them
excretory organs of excrementious juices; but as the vapour exhaled from
vegetables has no taste, this idea is no more probable than the other;
add to this that in moist weather, they do not appear to perspire or
exhale at all.

The internal surface of the lungs or air-vessels in men, are said to be
equal to the external surface of the whole body, or about fifteen square
feet; on this surface the blood is exposed to the influence of the
respired air through the medium however of a thin pellicle; by this
exposure to the air it has its colour changed from deep red to bright
scarlet, and acquires something so necessary to the existence of life,
that we can live scarcely a minute without this wonderful process.

The analogy between the leaves of plants and the lungs or gills of
animals seems to embrace so many circumstances, that we can scarcely
withhold our assent to their performing similar offices.

I. The great surface of the leaves compared to that of the trunk and
branches of trees is such, that it would seem to be an organ well
adapted for the purpose of exposing the vegetable juices to the
influence of the air; this however we shall see afterwards is probably
performed only by their upper surfaces, yet even in this case the
surface of the leaves in general bear a greater proportion to the
surface of the tree, than the lungs of animals to their external
surfaces.

2. In the lungs of animal, the blood after having been exposed to the
air in the extremities of pulmonary artery, is changed in colour from
deep red to bright scarlet, and certainly in some of its essential
properties; it is then collected by the pulmonary vein and returned to
the heart. To shew a similarity of circumstance in the leaves of plants
the following experiment was made, June 24, 1781: A stalk with leaves
and seed-vessels of large spurge (Euphorbia helioscopia) had been
several days placed in a decoction of madder (Rubia tinctorum) so that
the lower part of the stem, and two of the undermost leaves were
immersed in it. After having washed the immersed leaves in clear water,
I could readily discern the colour of the madder passing along the
middle rib of each leaf. This red artery was beautifully visible both on
the under and upper surface of the leaf; but on the upper side many red
branches were seen going from it to the extremities of the leaf, which
on the other side were not visible except by looking through it against
the light. On this under side a system of branching vessels carrying a
pale milky fluid were seen coming from the extremities of the leaf, and
covering the whole underside of it, and joining into two large veins,
one on each side of the red artery in the middle rib of the leaf, and
along with it descending to the footstalk or petiole. On slitting one of
these leaves with scissars, and having a common magnifying lens ready,
the milky blood was seen oozing out of the returning veins on each side
of the red artery in the middle rib, but none of the red fluid from the
artery.

All these appearances were more easily seen in a leaf of Picris treated
in the same manner; for in this milky plant the stems and middle rib of
the leaves are sometimes naturally coloured reddish, and hence the
colour of the madder seemed to pass further into the ramifications of
their leaf-arteries, and was there beautifully visible with the
returning branches of milky veins on each side.

3. From these experiments the upper surface of the leaf appeared to be
the immediate organ of respiration, because the coloured fluid was
carried to the extremities of the leaf by vessels most conspicuous on
the upper surface, and there changed into a milky fluid, which is the
blood of the plant, and then returned by concomitant veins on the under
surface, which were seen to ooze when divided with scissars, and which
in Picris, particularly render the under surface of the leaves greatly
whiter than the upper one.

4. As the upper surface of leaves constitutes the organ of respiration,
on which the sap is exposed in the terminations of arteries beneath a
thin pellicle to the action of the atmosphere, these surfaces in many
plants strongly repel moisture, as cabbage-leaves, whence the particles
of rain lying over their surfaces without touching them, as observed by
Mr. Melville (Essays Literary and Philosop. Edinburgh) have the
appearance of globules of quicksilver. And hence leaves laid with the
upper surfaces on water, wither as soon as in the dry air, but continue
green many days, if placed with the under surfaces on water, as appears
in the experiments of Mons. Bonnet (Usage des Fevilles.) Hence some
aquatic plants, as the Water-lily (Nymphoea) have the lower sides of
their leaves floating on the water, while the upper surfaces remain dry
in the air.

5. As those insects, which have many spiracula, or breathing apertures,
as wasps and flies, are immediately suffocated by pouring oil upon
them, I carefully covered with oil the surfaces of several leaves of
Phlomis, of Portugal Laurel, and Balsams, and though it would not
regularly adhere, I found them all die in a day or two.

Of aquatic leaves, see Note on Trapa and on Fucus, in Vol. II. to which
must be added that many leaves are furnished with muscles about their
footstalks, to turn their upper surfaces to the air or light, as Mimosa
and Hedysarum gyrans. From all these analogies I think there can be no
doubt but that leaves of trees are their lungs, giving out a phlogistic
material to the atmosphere, and absorbing oxygene or vital air.

6. The great use of light to vegetation would appear from this theory to
be by disengaging vital air from the water which they perspire, and
thence to facilitate its union with their blood exposed beneath the thin
surface of their leaves; since when pure air is thus applied, it is
probable, that it can be more readily absorbed. Hence in the curious
experiments of Dr. Priestley and Mr. Ingenhouze, some plants purified
air less than others, that is, they perspired less in the sunshine; and
Mr. Scheele found that by putting peas into water, which about half-
covered them, that they converted the vital air into fixed air, or
carbonic acid gas, in the same manner as in animal respiration. See Note
XXXIV.

7. The circulation in the lungs or leaves of plants is very similar to
that of fish. In fish the blood after having passed through their gills
does not return to the heart as from the lungs of air-breathing animals,
but the pulmonary vein taking the structure of an artery after having
received the blood from the gills, which there gains a more florrid
colour, distributes it to the other parts of their bodies. The same
structure occurs in the livers of fish, whence we see in those animals
two circulations independent of the power of the heart, viz. that
beginning at the termination of the veins of the gills, and branching
through the muscles; and that which passes through the liver; both which
are carried on by the action of those respective arteries and veins.
Monro's Physiology of Fish, p. 19.

The course of the fluids in the roots, leaves, and buds of vegetables
seems to be performed in a manner similar to both these. First the
absorbent vessels of the roots and surfaces unite at the footstalk of
the leaf; and then, like the Vena Portarum, an artery commences without
the intervention of a heart, and spreads the sap in its numerous
ramifications on the upper surface of the leaf; here it changes its
colour and properties, and becomes vegetable blood; and is again
collected by a pulmonary vein on the under surface of the leaf. This
vein, like that which receives the blood from the gills of fish, assumes
the office and name of an artery, and branching again disperses the
blood upward to the bud from the footstalk of the leaf, and downward to
the roots; where it is all expended in the various secretions, the
nourishment and growth of the plant, as fast as it is prepared.

II. The organ of respiration already spoken of belongs particularly to
the shoots or buds, but there is another pulmonary system, perhaps
totally independent of the green foliage, which belongs to the
fructification only, I mean the corol or petals. In this there is an
artery belonging to each petal, which conveys the vegetable blood to its
extremities, exposing it to the light and air under a delicate membrane
covering the internal surface of the petal, where it often changes its
colour, as is beautifully seen in some party-coloured poppies; though it
is probable some of the iridescent colours of flowers may be owing to
the different degrees of tenuity of the exterior membrane of the leaf
refracting the light like soap-bubbles, the vegetable blood is then
returned by correspondent vegetable veins, exactly as in the green
foliage; for the purposes of the important secretions of honey, wax, the
finer essential oil, and the prolific dust of the anthers.

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