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Chambers's miscellany of useful and entertaining tracts (Volume v.5-6) online

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over its trackless fields and endless mazes.

Here, however, we must close our record of microscopic plants,
which, it will be seen, belong chiefly to the mosses, lichens, fungi,
and other forms of flowerless vegetation. Zoologists tell us, when
speaking of animalcules, that not a drop of stagnant water, not
a speck of vegetable or animal tissue, but has its own appro-
priate inhabitants. The same may be remarked of plants ; for we
cannot point to a speck of surface, unless chilled by everlasting



cold, or parched by continuous drought, that has not its owa
pecuUar veg^etation. The spores or seeds of these minute para-
sites are almost infinitesimallY small : they are floating: above
and around us, unperceived by the naked eye, ready to fall and
germinate wherever fitting* conditions are presented. Nay, as
certain changes in animal tissue are ascribed to animalcules, so
have certain changes in organised substances, such as fermenta-
tion, been ascribed to vegetable growth. Yeast, according to this
view, is a true vegetable, consisting of minute organised cells or
spherules, which propagate with amazing rapidity so long as
they tind their proper nutriment in the fermenting liquid. Nor
is there anything more incredible in the fact, that the little
globular yeast plant should extract its nutriment from the fluid
on which it floats, than that the "water-flannel should extract it3
starch or lime from the water which it covers.


Under this head v»-e comprehend such plants as stand out in
bold relief from the rest of the vegetable kingdom for some noted
peculiarity in structure, habits, or properties. It is true that
every plant has its own specilic distinctions ; but there are seve-
ral which seem to stand apart as the curiosities of vegetation,
just as the ornithorhyncus and girafle stand isolated among ani-
mals. They have no congeners in the peculiarity that renders
them remarkable.

The cow tree, or palo de vaca of South America, is one of
the most interesting of this class. It is known to botanists as
the Galactodendron utile, or useful milk tree, and belongs to
the Urticacecp, or nettle tribe, the herbaceous members of which
have their juice thin and watery, while in the ligneous species
it is milky and viscous. The cow tree is a native of the
Caraccas, and grows in rocky situations at an elevation of nearly
3000 feet. It is thus described by Baron Humboldt :— " On the
barren flank of a rock grows a tree with dry and leathery leaves ;
its large woody roots can scarcely penetrate into the stonj^ soil.
For several months in the year not a single shower moistens
its foliage. Its branches appear dead and dried ; yet, as soon as
the trunk is pierced, there flows from it a sweet and nourishing
milk. It is at sunrise that this vegetable fountain is most abun-
dant. The natives are then to be seen hastening from all quarters,
furnished with large bowls to receive the milk, which grows
yellow, and thickens at the surface. Some drain their boAvls
under the tree, while others carry home the juice to their chil-
dren ; and you might fancy you saw the family of a cowherd
gathering around him, and receiving from him the produce of
his kine. The milk obtained by incisions made in the trunk is
glutinous, tolerably thick, free from all acridity, and of an
agreeable and balmy smell. It was offered to us in the shell of
the trituros or calabash tree. We drank a considerable quantity



of it in the evening before going to bed, and very early in the
morning, without experiencing the slightest injurious effect. The
viscosity of the milk is the only thing that renders it somewhat
disagreeable. The negroes and free labourers drink it, dip^^ing
into it their maize or cassava bread.'' Sir R. Kerr Porter de-
scribes the palo de vaca as a tree of large dimensions, men-
tioning that he measured one somewhat more than 20 feet in
circumference at about 5 feet from the root. This colossal stem
ran up to the height of 60 feet, perfectly uninterrupted by either
leaf or branch, when its vast arms and minor branches, most
luxuriantly clothed with foliage, spread on every side fully 25 or
SO feet from the trunk, and rose to an additional height of 40
feet, so that this stupendous tree was quite 100 feet hig'h in all.
Others were seen at a distance of still larger dimensions.

Equal in utility with the cow tree in yielding an agreeable
beverage, but belonging to a very different order, is the ravanala,
or traveller's tree of INIadagascar. This curious plant belongs to
the same tribe as the plantain and banana; namely, the Musacece,
and is known to botanists by the name of Urania speciosa. It
forms a striking feature in the scenery, as it does in the economy
of its native country, and is thus described by Mr Backhouse in
his recent Visit to the Mauritius and South Africa : — " Clumps
of these trees, composed of several stems rising* from the same
root, are scattered over the country in all directions. The trunks,
or, more properly, root-stocks, Avhich are about 3 feet in circum-
ference, sometimes attain to 30 feet in heig"ht ; but whether of
this elevation, or scarcely emerging above ground, they support
grand crests of leaves of about 4 feet long and 1 foot wide, but
often torn into comb-like shreds. The head is of a fan-like form,
and the flowers, which are not striking for their beauty, are white,
and produced from large horizontal green sheaths. The foot-
stalks of the leaves, which are somewhat shorter than the leaves
themselves, yield a copious supply of fresh water, very grateful
to the traveller, on having their margin cut away near to the
base, or forced from contact v/ith those immediately above them,
especially those about the middle of the series. The root-stock is
of a soft cellular substance, and the fruit, which resembles a small
banana, is dry, and not edible. This remarkable vegetable pro-
duction is said to grow in the most arid countries, and thus to
be provided for the refreshment of man in a dry and thirsty land.
Probably the water may originate in the condensation of dew, and
be collected and retained by the peculiar structure of the leaf: it
has a slight taste of the tree, but is not disagreeable."

The Pitclier-Plant, or Nejyenthes distillatoria, is another of
those fluid-containing plants whose structure and adaptation
strike us with wonder and admiration. It is the type of the
recently-established order JVepenthace^e, and is commonly met
with in Ceylon and other islands of the East, where it is known
hj the appropriate name of pitcher-plant, on account of the sin-


gular flagon-sliapecl appendage which holds the water. " Being
the inhabitant of a tropical climate," says Barrow in his Cochin-
China, " and found on the most dry and stony situations, nature
has furnished it with the means of an ample sunply of moisture,
without which it would have withered and perished. To the
foot-stalk of each leaf, near the base, is attached a kind of bag-,
shaped like a pitcher, of the same consistency and colour as the
leaf in the early stage of its growth, but changing with age to a
reddish purple. It is girt round with an oblique band or hoop, and
covered with a lid neatly fitted, and moveable on a kind of hing'e
or strong" fibre, which, passing over the handle, connects the
vessel with the leaf. By the shrinking or contracting of this
fibre, the lid is drawTi ojoen whenever the weather is showery or
dew falls, which would appear to be just the contrary of what
usually happens in nature, thoug-h the contraction probably is
occasioned by the hot dry atmosphere ; and the expansion of the
fibre does not take place till the moisture has fallen and saturated
the pitcher. "V^Tien this is the case, the cover falls down, and it
closes so firmly, as to prevent any evaporation taking' place. The
water, when gradually absorbed through the handle into the
foot-stalk of the leaf, gives ^-igour to the leaf itself, and suste-
nance to the plant. As soon as the pitchers are exhausted, the
lids again open, to admit whatever moisture may fall ; and when
the plant has produced its seed, and the dry season fairly sets in,
it withers, with all the covers of the j)itchers standing' open."
The accompanying" figure represents a leaf of the nepenthes, with

" its curious appen-
dage and fittings,
than the structure
of which nothing
could be more tho-
roughly adapted
for accomplishing
the end in view.
Under this head may be mentioned the shea, or butter tree,
from the kernel of which the Africans extract a fatty substance
that is whiter, finer, and equal in flavour to the best butter made
from cow's milk, with this advantage, that it will keep without
salt for many months ; the tallow tree, or candleberry myrtle,
the nut of which yields a waxy substance used in the manufac-
ture of candle in America; the India-rubber tree, from the
thickened juice of which caoutchouc is obtained ; the bread-fruit ;
and many others ; but as these have been noticed in various
popular works, and as our space is limited, we pass on to the
curious phenomena of


We are aware that warm-blooded animals have the power of
keeping up a certain temperature within them, which varies at



certain stages of tlieii* growth, and perhaps pei-iodically. This
result is obtained by respiration — the oxygen of the atmosphere
uniting with the carbon of their blood, and producing a species
of combustion. The more fresh air we breathe, the greater the
heat of our bodies, so long as we take proper food to afford the
carbon. A similar though less understood phenomenon seems to
take place in the respiration of plants. Heat is always disen-
gag;ed when gaseous products are liberated ; and as vegetables
respire, however slovvd}^, a certain degree of heat must be pro-
duced during that jDrocess. In germination, heat is sensibly
evolved : a piece of ice placed on a growing- leaf-bud dissolves,
when it would remain unchanged in the open air ; and experi-
ment has proved that the surface of growing plants is three or
four degrees higher than the surrounding medium. Ag-ain, the
internal temperature of a large trunk is always higher than the
surrounding atmosphere; and though young shoots are some-
times frozen through, the general structure of the wood and
bark is such as to conduct heat so slowly, that the internal
warmth is never reduced beyond wdiat seems necessary to vitality.
During germination, this heat is most perceptible ; and though
it be rapidly dissipated by the extent of surface exposed to the
air, 110 degrees have been noted during- malting, and 87 in the
flower of a geranium, w^hen the atmosphere was only at 81.

The luminosity of plants— that is, the evolution of light either
from living or dead vegetable structure — is a still more curious
phenomenon. Flowers of an orange colour, as the marigold and
nasturtium, occasionally present a luminous appearance on still
warm evenings ; this light being either in the form of slight
electric sparlcs, or steadier, like the phosphorescence of the glow-
Avorm. Thus the tube-rose has been observed in sultry evenings,
after thunder, when the air was highl}'' charged with electric
fluid, to dart small scintillations of lurid flame in great abundance
from such of its flowers as are fading. Sometimes the leaves
emit the light, as appears by the following record : — " In the
garden of the Duke of Buckingham at StovvC, on the evening of
Friday, Sept. 4, 1835, during a storm of thunder and lightning,
accompanied by heavy rain, the leaves of the flower called
CEnothcra macrocarpa, a bed of which is in the garden imme-
diately ojiposite the windows of the manuscript library, were
observed to be brilliantly illuminated by phosphoric light. Dur-
ing the intervals of the flashes of lightning- the night was ex-
ceedingly dark, and nothing else could be distinguished in the
g-loom except the bright lig-ht upon the leaves of these flowers.
The luminous appearance continued uninterruptedly for a con-
siderable length of time, but did not appear to resemble any elec-
tric efl'ect." Certain fungi which grow in warm and moist
situations produce a similar phosphorescence ; and decaying vege-
tables, like dead animal matter, have been observ^ed to emit the
same kind of luminosity. From these examples, it would appear



that the lig-ht was sometimes due to electricity, and sometimes
to a true phosphorescence, like that of the g"low-%vorm. Luminosity
may, hoM-ever, be produced by actual combustion of the volatile
oils, which are continually flying- oif from certain plants : those
of the Dictamnus albus will inflame upon the application of a
match, so that the bush may thus be enveloped in flames, and
yet not be consumed.


There is no difficulty in understanding" what is meant by
motion and sensation in animals ; they move by muscular con-
tractions and expansions, and feel throug'h their nervous struc-
ture. When, however, we speak of motion and sensation in
plants, the phenomena assume a more puzzling- aspect. Yeg-e-
tables have, no doubt, woody fibres, sap vessels, spiral vessels,
kc. ; but then these have no affinity to the veins or muscles oif
animals. They may serve the same purposes in their economj^,
but it would be transg-ressing^ all rules of sound science to estab-
lish an identity between the tv/o sets of organs ; to call, for
example, these vessels the nerves of plants, and to ascribe to
them the faculty of sensation, when there is nothing- beyond the
faintest analogy between their structures. Althoug-h plants may
not feel, however, as the higher animals do, which have a regular
nervous structure and a brain, yet the}' may possess an irrita-
bility analogous to, or even identical with, that possessed by
polyps and sponges. Polyps have no discernible nervous struc-
ture, yet they seem to feel, to contract, and expand at will ; and
so may the vitality of plants depend upon the existence of an
irritability, if not similar, at least analogous. It is a beautiful
and exalting idea, certainly, to believe in the sensation and
enjoyment of vegetable life ; to people the fields and forests with
structures rejoicing- in the light and sunshine of summer, exult-
ing' in the reproduction of their kind, and becoming dormant
during the rigours of winter ; to feel and declare with the poet —

" And 'tis my faith that every flower
Enjoys the air it breathes."

Science, however, is more rigid and cautious than poetical fancy ;
and, in the present state of our knowledg-e, little more can be
done than merely to describe the phenomena.

The principal phenomena of vegetable irritability may be
divided into three kinds — those caused by atmospheric influence,
those depending upon the touch of other bodies, and those which
appear to be perfectly spontaneous. Atmospheric influence occa-
sions the closing- of the leaves over the part of the tender-growing
shoot at night, as may be observed in the chick weed and other
commxon plants, which are then said to sleep. The folding- of some
flowers in the absence of the sun, and the opening- of others as
soon as that luminarv has withdrawn its beams, are ascribable to



a similar cause. The wliite marig-old closes its flowers on the
approach of rain, and the dwarf celandrina folds up its brio-ht
crimson corolla about four o'clock every afternoon. The evening
primrose, on the contrary, will not open its large flowers till the
sun has sunk below the horizon ; and the nig-ht-blowing" cereus
only expands its mag-nificent blossoms about midnight. Some
flowers are so regular in their hours of opening and shutting, that
Linnaeus formed what he called Flora's Time-piece, in which each
hour was represented by the flower which opened or closed at
that particular time.

The irritability produced by external touch is a familiar, but
little understood phenomenon. The movements of the sensitive
plant are well known ; and it is also known that if the ripe seed-
vessels of the noli-me-tangere be touched in the slightest manner,
they will open with elasticity, and scatter their contents. The
I'eservoirs which contain the milky juice of the wild lettuce
are so remarkably irritable, that the gentlest touch is sufficient
to cause it to be ejected from them with considerable force.
When this plant is about to flower, if an insect happens to
crawl over the surface of the stalk anywhere near to its sum-
mit, a jet of viscous milk is joropelled, which, if it happens to
strike the tiny intruder, glues him to the spot. In the same

Venns's Fly-trap, and Sun-dew.

manner the fruit of the squirting cucumber throws out its seeds
and the moist pulp in which they are contained with great
violence, and to a considerable distance. The stamens of the bar-
berrv, when touched with a pin, spring forward, and ajDpear to


make a bow to the stig-ma, after which they return to their jDro-
per position. The most remarkable instance of irritabiHty by
contact is that exhibited by Yenus's fly-trap, Dioncea vmscipulay
a native of Canada, and nearly allied to the common sun-dew of
the British commons. Its flowers have nothing- remarkable about
them, except that their petals roll up when they are about to
decay ; but the leaves are very curiously constructed. They
have broad leaf-like petioles, at whose extremity are two fleshy
lobes, which form the real leaf, and which are armed with strong-
sharp spines, three on the blade of each lobe, and a fring-e of
long-er spines round the margin, as is shown in the preceding-
figure. When an insect touches the base of the central spines,
the leaf collapses, and the poor insect is caught, being- either
impaled by the central spines, or entrapped by the others. The
leaf then remains closed, the fringe of long spines being* firmly
interlaced and locked together, till the body of the insect has
wasted away. This apparatus being- the nearest approach to a
stomach which has been yet observed in plants, an experiment
was tried some years ago of feeding a dionsea with very small
particles of raw meat, when it was found that the leaves closed
in the same way as they would have done over an insect, and
did not open ag-ain till the meat was consumed.

The spontaneous movements of plants are much more difficult
to be accounted for than those occasioned by atmospheric influ-
ence, or by external touch. AYe can fancy light and heat con-
tracting- or dilating the vessels, and thus occasioning* flowers to
open or shut, and leaves to fold or unfold ; but plants have some
movements for which there is apparently no external cause. In
the Hedysarum gyrans, for examjDle, which has compound leaves,
the terminal leaflet of which never moves except to fold itself
close down to its own stalk ; but the side leaflets have such eccen-
tric movements, as to render it difficult, if not impossible, to ex-
plain them, and which might appear, indeed, to a fanciful mind
as though the whole plant were actuated by a feeling of caprice.
Generahy, all the leaflets twist and whiii themselves about in an
extraordinary manner, though the air of the house in which
they g-row is perfectly still ; but frequently the leaflets on only
one side will be afifected, and sometimes only a sing-le leaflet will
move, or all will become motionless together ; and when this is
the case, it is quite in vain to attempt to set them again in mo-
tion by touching them ; though sometimes in a moment, as if
from the pure love of mischief, after the touching- has ceased, the
leaflets will begin to move again as rapidly as before. In the like
manner the side leaflets frequently continiie their eccentric move-
ments all night, while the terminal leaflet remains quietly folded
up, and apparently fast asleep. M. Dutrochet ascribes all these
movements to an interior and vital excitation ; indeed life ap-
pears to be intimately connected with irritability, as the latter
quality exists only in plants in a vigorous condition.



The vitality of plants may be destroyed by giving' them dele-
t^erious or j)oisonous substances. These facts have been estab-
lished principally b}^ the experiments of Marcet and Macaire.
Common kidney beans which had been watered with a decoction
of arsenic faded in the course of a few hours ; they then began
to turn yellow, and on the third day were dead. A lilac was
also killed by having arsenic introduced into a slit in one of its
branches. Mercury, under the form of corrosive sublimate, pro-
duced the same effects as arsenic ; but vvdien used as quicksilver,
no results were observed. Vegetable poisons have been proved
to be equally injurious to other plants as mineral ones ; a solution
of nux vomica killed some kidney beans in the course of a few
hours. Prussic acid had the same effect in the course of a day,
and deadly nightshade in about four days ; while spirits of wine
killed the plant to which it was administered in a few hours.
These experiments also tend to confirm the idea of sensation in
vegetables ; in other words, that plants have life more closely
analog'ous to that of animals than most people suppose ; that
however different their feelings may be from that of ours, that
they are at least endowed with sensation ; and that the belief in
their enjoyment of the air and sunshine may be something more
than a mere poetical fancy.

Such is a rapid glance at the more prominent points of a sub-
ject which would require as many volumes for its full explana-
tion as we have devoted pages. Our descriptions, imperfect as
they are, may serve, however, the useful purpose of directing the
attention of many to an unexhaustible field of inquiry, and of
the purest and most delightful recreation. The study of nature
is open to every one, whatever his means or circumstances. The
objects of jDursuit are above, beneath, and around us ; they are
ever fresh and enticing • and we feel that we are as far from
having exhausted their wonders to-day as we were twenty years

** Not p. plant, a leaf, a flower, but contains
A folio volume. We may read, and read,
And read again, and still find something new — •
Something to please, something to instruct,
Even in the noisome weed."






£^ T is an ancient Mariner,

^^ And he stoppeth one of three ; ^IS'SL Sa"„;^

^^ Bj thy long- gray beard and glit- bidden to a wedding

^"^l terino* eye • feast, and detaincth

Now wherefore stopp'st thou me ? ^^^'

The hridegToom's doors are opened wide,
And I am next of kin ;
The g-uests are met, the feast is set :
Mayst hear the merry din."

He holds him with his skinny hand ;
" There was a ship," quoth he.
" Hold off! unhand me, gray-beard loon ! "
Eftsoons his hand dropt he.

He holds him with his glittering eye-
The wedding-guest stood still,
And listens like a three-years' child :
The Mariner hath his will.
No. 59.

The wedding- guest is
spell-bound by the eye
of the old seafaring
man, and constrained
to hear his tale.


The wedding'-guest sat on a stone :
He cannot choose but hear ;
And thus spake on that ancient man,
The hrig-ht-eyed Mariner.

The ship was cheered, the harbour cleared,

Merrily did we drop

Below the kirk, below the hill.

Below the lig-hthouse top.

The sun came up upon the left,
Out of the sea came he ;
And he shone bright, and on the right
Went down into the sea.

Higher and higher every day,

Till over the mast at noon

The wedding'-guest here beat his breast,
For he heard the loud bassoon.

The bride hath paced into the hall,
Red as a rose is she :
Nodding their heads, before her goes
The merry minstrelsy.

The wedding-guest he beat his breast.
Yet he cannot choose but hear !
And thus spake on that ancient man,
The bright-eyed Mariner.

And now the storm-blast came, and he
Was tyrannous and strong ;
He struck with his overtaking wings.
And chased us south along.

With sloping masts, and dipping prow,
As who pursued with yell and blow
Still treads the shadow of his foe,
And forward bends his head ;
The ship drove fast, loud roared the blast.
And southward aye we fled.

And now there came both mist and snow,
And it grew wondrous cold ;
And ice mast high came floating by,
As green as emerald.

Online LibraryWilliam ChambersChambers's miscellany of useful and entertaining tracts (Volume v.5-6) → online text (page 56 of 59)