Chapter XVI (2)

"In these tropical forests each plant and tree seems to be striving
to outvie its fellow, struggling upward toward light and
air--branch, and leaf, and stem--regardless of its neighbors.
Parasitic plants are seen fastening with firm grip on others, making
use of them with reckless indifference as instruments for their own
advancement. Live and let live is clearly not the maxim taught in
these wildernesses. There is one kind of parasitic tree very common
near Pará which exhibits this feature in a very prominent manner. It
is called the Sipó Matador, or the Murderer Liana. It belongs to the
fig order, and has been described by Von Martins in the 'Atlas to
Spix and Martius's Travels.' I observed many specimens. The base of
its stem would be unable to bear the weight of the upper growth; it
is obliged, therefore, to support itself on a tree of another
species. In this it is not essentially different from other climbing
trees and plants, but the way the matador sets about it is peculiar,
and produces certainly a disagreeable impression. It springs up
close to the tree on which it intends to fix itself, and the wood of
its stem grows by spreading itself like a plastic mould over one
side of the trunk of its supporter. It then puts forth from each
side an arm-like branch, which grows rapidly, and looks as though a
stream of sap were flowing and hardening as it went. This adheres
closely to the trunk of the victim, and the two arms meet on the
opposite side and blend together. These arms are put forth at
somewhat regular intervals in mounting upward, and the victim when
its strangler is full grown becomes tightly clasped by a number of
inflexible rings. These rings gradually grow larger as the murderer
flourishes, rearing its crown of foliage to the sky mingled with
that of its neighbor, and in course of time they kill it by stopping
the flow of its sap. The strange spectacle then remains of the
selfish parasite clasping in its arms the lifeless and decaying body
of its victim, which had been a help to its own growth. Its ends
have been served--it has flowered and fruited, reproduced and
disseminated its kind; and now when the dead trunk moulders away,
its own end approaches; its support is gone, and itself also falls."

The strangling properties of some of the fig-tree family are indeed very remarkable, and may be witnessed not only in South America, but in India, Ceylon, and Australia. Frazer observed several kinds of _Ficus_, more than 150 feet high, embracing huge ironbark trees in the forests at Moreton Bay. The _Ficus repens_, according to Sir Emerson Tennent, is often to be seen clambering over rocks, like ivy, turning through heaps of stones, or ascending some tall tree to the height of thirty or forty feet, while the thickness of its own stem does not exceed a quarter of an inch. The small plants of this family, of which the Murdering Liana is one species, grow and reproduce their kind from seeds {183} deposited in the ground; but the huge representatives of the family, such as the banyan-tree, whose

"Bended twigs take root, and daughters grow
About the mother tree;"

and the Peepul, or sacred Bo-tree of the Buddhists (_Ficus religiosa_), originate from seeds carried by birds to upper portions of some palm or other tree. Fig-trees, as Sir E. Tennent has remarked, are "the Thugs of the vegetable world; for, though not necessarily epiphytic, it may be said that, in point of fact, no single plant comes to perfection or acquires even partial development without the destruction of some other on which to fix itself as its supporter." The mode of growth of these trees is well described by the excellent writer just mentioned, and we shall make use of his own language:

"The family generally make their first appearance as slender roots
hanging from the crown or trunk of some other tree, generally a
palm, among the moist bases of whose leaves the seed carried thither
by some bird which had fed upon the fig begins to germinate. This
root, branching as it descends, envelops the trunk of the supporting
tree with a net-work of wood, and at length, penetrating the ground,
attains the dimensions of a stem. But, unlike a _stem_, it throws
out no buds or flowers; the true stem, with its branches, its
foliage, and fruit, springs upward from the crown of the tree whence
the root is seen descending; and from it issue the pendulous
rootlets, which on reaching the earth fix themselves firmly, and
form the marvellous growth for which the banyan is so celebrated. In
the depth of this grove the original tree is incarcerated till,
literally strangled by the folds and weight of its resistless
companion, it dies and leaves the fig in undisturbed possession of
its place." [Footnote 25]

[Footnote 25: "Ceylon," i., p. 95]

But not trees alone do these vegetable garrotters embrace in their fatal grasp, ancient monuments are also destroyed by these formidable assailants. Sir E. Tennent has given an engraving of a fig-tree on the ruins at Pollanarrua, in Ceylon, which had fixed itself on the walls---a curious sight, indeed--"its roots streaming downward over the ruins as if they had once been fluid, following every sinuosity of the building and terraces till they reach the earth." An extremely interesting series of drawings is now to be seen in the Linnean Society's room at Burlington House, illustrating the mode of growth of another strangling or murdering tree, of New Zealand, belonging to an entirely different order from that to which the figs belong (_Urticaceae_), namely, to one of the _Myrtaceae_. The association of garrotting habits with those of the stinging nettle family is apt enough, we may be inclined to think; but it is rather disappointing to meet with these disagreeable peculiarities in the case of the myrtle group; but such is the fact: the Rata, or _Metrosideros robusta_--as we believe is the species---climbs to the summits of mighty trees of the forest of Wangaroa, and kills them in its iron grasp. But, notwithstanding these unpleasant impressions which "the reckless energy of the vegetation might produce" in the traveller's mind, there is plenty in tropical nature to counteract them:

"There is the incomparable beauty and variety of the foliage, the
vivid color, the richness and exuberance everywhere displayed, which
make the richest woodland scenery in northern Europe a sterile
desert in comparison. But it is especially the enjoyment of life
manifested by individual existences which compensates for the
destruction and pain caused by the inevitable competition. Although
this competition is nowhere more active, and the dangers to which
each individual is exposed nowhere more numerous, yet nowhere is
this enjoyment more vividly displayed."

Mr. Bates mentions a peculiar feature in some of the colossal trees which here and there monopolize a large {184} space in the forests. The height of some of these giants he estimates at from 180 to 200 feet, whose "vast dome of foliage rises above the other forest trees as a domed cathedral does above the other buildings in a city." In most of the large trees of different species is to be seen "a growth of buttress-shaped projections around the lower part of their stems. The spaces between these buttresses--which are generally thin walls of wood--form spacious chambers, and may be compared to stalls in a stable; some of them are large enough to hold half-a-dozen persons." What are these buttresses, how do they originate, and what is their use? We have already seen how great is the competition amongst the trees of a primeval forest, and how every square inch is eagerly battled for by the number of competitors. In consequence of this it is obvious that lateral growth of roots in the earth is a difficult matter. "Necessity being the mother of invention," the roots, unable to expand laterally, "raise themselves ridge-like out of the earth, growing gradually upward as the increasing height of the tree required augmented support." A beautiful compensation, truly, and full of deep interest! As Londoners add upper stories to their houses where competition has rendered lateral additions impossible, so these gigantic trees, in order to sustain the massive crown and trunk, strengthen their roots by upper additions.

One of the most striking features in tropical scenery is the suddenness with which the leaves and blossoms spring into full beauty. "Some mornings a single tree would appear in flower amidst what was the preceding evening a uniform green mass of forest,--a dome of blossom suddenly created as if by magic." In the early mornings, soon after dawn, the sky is always without a cloud, the thermometer marking 72° or 73° Fahr. Now all nature is fresh, and the birds in the full enjoyment of their existence, the "shrill yelping" of the toucans being frequently heard from their abode amongst the wild fruit-trees of the forest; flocks of parrots appear in distinct relief against the blue sky, always two by two, chattering to each other, the pairs being separated by regular intervals, too high, however, to reveal the bright colors of their plumage. The greatest heat of the day is about two o'clock, by which time, the thermometer being 92° or 93° Fahr., "every voice of bird or mammal is hushed; only in the trees is heard at intervals the harsh whirr of a cicada. The leaves, which were so fresh and moist in early morning, now become lax and drooping, and the flowers shed their petals. The Indian and mulatto inhabitants sleep in their hammocks, or sit on mats in the shade, too languid even to talk."

Mr. Bates has given a graphic picture of tropical nature at the approach of rain:

"First, the cool sea-breeze which commenced to blow about ten
o'clock, and which had increased in force with the increasing power
of the sun, would flag and finally die away. The heat and electric
tension of the atmosphere would then become almost insupportable.
Languor and uneasiness would seize on every one; even the denizens
of the forest betraying it by their motions. White clouds would
appear in the east and gather into cumuli, with an increasing
blackness along their lower portions. The whole eastern horizon
would become almost suddenly black, and this would spread upward,
the sun at length becoming obscured. Then the rush of a mighty wind
is heard through the forest, swaying the tree-tops; a vivid flash of
lightning bursts forth, then a crash of thunder, and down streams
the deluging rain. Such storms soon cease, leaving bluish-black
motionless clouds in the sky until night. Meanwhile all nature is
refreshed; but heaps of flower petals and fallen leaves are seen
under the trees. Toward evening life revives again, and the ringing
uproar is resumed from bush and tree. {185} The following morning
the son again rises in a cloudless sky, and so the cycle is
completed; spring, summer, and autumn, as it were, in one tropical
day."

With regard to animal life in the Amazonian forests, it appears that there is a great variety of mammals, birds, and reptiles, but they are very shy, and widely scattered. Brazil is poor in terrestrial animals, and the species are of small size. "The huntsman would be disappointed who expected to find here flocks of animals similar to the buffalo herds of North America, or the swarms of antelopes and herds of ponderous pachyderms of southern Africa."

It has already been observed that the mammals of Brazil are, for the most part, arboreal in their habits; this is especially the case with the monkeys, or _Cebidae_, a family of quadrumamous animals peculiar to the new world. The reader may observe the habits of some species of this group in the monkey-house of the Zoological Society's Gardens in Regent's Park. The strong muscular tail, with its naked palm under the tip, which many of the Cebidae possess, renders them peculiarly well adapted to a forest life. Mr. Bates states that thirty-eight species of this family of monkey inhabit the Amazon region, and considers the Coaitás, or spider-monkeys, "as the extreme development of the American type of apes." The flesh of one species of Coaitás is much esteemed as an article of food by the natives in some parts of the country. The Indians, we are told, are very fund of Coaitás as pets.

Some of our readers are doubtless acquainted with the name of Madame Maria Sibylla Merian, a German lady who was born about the middle of the seventeenth century. She was much devoted to the study of natural history, and travelled to Surinam for the purpose of making drawings of its animal productions; many of these drawings are now in the British Museum. This estimable lady, amongst other curiosities of natural history, affirmed the two following ones:--1. The lantern-fly (_Fulgora lanternaria_) emits so strong a light from its body as to enable a person in the night-time to read a newspaper by it. 2. The large spider (_Mygale_) enters the nests of the little humming-birds, and destroys the inmates. It would occupy too much time to tell of the mass of evidence which was adduced in denial of these recorded facts, but, suffice it to say that Madame Merian was set down as an arch-heretic and inventor, and that no credit was attached to her statements. With regard to the first-named heresy, the opinion of modern zoologists is, that there is nothing at all improbable in the circumstance of the Fulgora emitting a strong light, as luminous properties are known to exist in other insects, but that the fact has been rather over-colored by the imagination of the worthy lady. As to the second question, about the bird-destroying propensities of the Mygale, let us hear the testimony of so thoroughly trustworthy a witness as Mr. Bates:

"In the course of our walk" (between the Tocantins and Cameta) "I
chanced to verify a fact relating to the habits of a large hairy
spider of the genus Mygale, in a manner worth recording. The species
was _M. avicularia_, or one very closely allied to it; the
individual was nearly two inches in length of body, but the legs
expanded seven inches, and the entire body and legs were covered
with coarse grey and reddish hairs. I was attracted by a movement of
the monster on a tree-trunk; it was close beneath a deep crevice in
the tree, across which was stretched a dense white web. The lower
part of the web was broken, and two small birds, finches, were
entangled in the pieces; they were about the size of the English
siskin, and I judged the two to be male and female. One of them was
quite dead, the other lay under the body of the spider not quite
dead, and was smeared with the filthy liquor or {186} saliva exuded
by the monster. I drove away the spider and took the birds, but the
second one soon died. The fact of species of Mygale sallying forth
at night, mounting trees, and sucking the eggs and young of
humming-birds, has been recorded long ago by Madame Merian and
Palisot de Beauvois; but, in the absence of any confirmation, it has
come to be discredited. From the way the fact has been related it
would appear that it had been merely derived from the report of
natives, and had not been witnessed by the narrators. Count
Langsdorff, in his 'Expedition into the Interior of Brazil,' states
that he totally disbelieved the story. I found the circumstances to
be quite a novelty to the residents here about. The Mygales are
quite common insects; some species make their cells under stones,
others form artistical tunnels in the earth, and some build their
dens in the thatch of houses. The natives call them _Aranhas
carangueijeiras_, or crab spiders. The hairs with which they are
clothed come off when touched, and cause a peculiar and almost
maddening irritation. The first specimen that I killed and prepared
was handled incautiously, and I suffered terribly for three days
afterward. I think this is not owing to any poisonous quality
residing in the hairs, but to their being short and hard, and thus
getting into the fine creases of the skin. Some Mygales are of
immense size. One day I saw the children belonging to an Indian who
collected for me with one of these monsters secured by a cord round
its waist, by which they were leading it about the house as they
would a dog."

The name of "ant" has only to be mentioned, and the strange habits of the various species immediately suggest themselves to the mind of the naturalist, who is always interested in, and amply repaid by, watching these insects with the closest scrutiny. Brazil abounds in ants, one species of which, the _Dinoponera grandis_, is an inch and a quarter in length; but by far the most interesting to the naturalist, as well as one of the most destructive to the cultivated trees of the country, is the leaf-carrying ant (_AEcodoma cephalotes_). In some districts, we are told, it is so abundant that agriculture is almost impossible, and everywhere complaints are heard of the terrible pest. This insect derives its specific name of _cephalotes_ from the extraordinary size of the heads belonging to two of the orders, which, with a third kind, constitute the colony. The formicarian establishment consists of: 1. Worker minors; 2. Worker majors; 3. Subterranean workers. The first-named kind alone does the real active work. The two last contain the individuals with the enormous heads; their functions are not clearly ascertained. In color they are a pale reddish-brown, and the thorax of the true worker, which is the smallest of the orders, is armed with three pairs of sharp spines; the head is provided with a pair of similar spines proceeding from the cheeks behind. This ant, known by the native name of Saüba, has long been celebrated for its habit of clipping off and carrying away, large quantities of leaves:

"When employed in this work," Mr. Bates says, "their processions
look like a multitude of animated leaves on the march. In some
places I found an accumulation of such leaves, all circular pieces,
about the size of a sixpence, lying on the pathway, unattended by
the ants, and at some distance from any colony. Such heaps are
always found to be removed when the place is revisited next day. In
course of time I had plenty of opportunities of seeing them at work.
They mount the tree in multitudes, the individuals being all worker
minors. Each one places itself on the surface of a leaf, and cuts
with its sharp scissor-like jaws, and by a sharp jerk detaches the
piece. Sometimes they let the leaf drop to the ground, where a
little heap accumulates until carried off by another relay of
workers; but generally each marches off {187} with the piece it has
operated upon and as all take the same road to their colony, the
path they follow becomes in a short time smooth and bare, looking
like the impression of a cart-wheel through the herbage."

The Saüba ant is peculiar to tropical America, and, though it is injurious to the wild native trees of the country, it seems to have a preference to the coffee and orange trees and other imported plants. The leaves which the Saüba cuts and carries away are used to "thatch the domes which cover the entrances to their subterranean dwellings, thereby protecting from the deluging rains the young broods in the nests beneath." The insects proceed according to a most orderly method, "the heavily-laden workers, each carrying its segment of leaf vertically, the lower edge secured in its mandibles, troop up, and cast their burdens on the hillock; another body of laborers place the leaves in position, covering them with a layer of earthy granules, which are brought one by one from the soil beneath." The labors of this curious insect are immense, and no obstacles stop their excavations. An allied species of Rio de Janeiro worked a tunnel under the bed of the river Parabyba, at a place where it is as broad as the Thames at London Bridge. These ants are sad rogues, being household plunderers and robbers of the farinha, or mandioca meal, of the poor inhabitants of Brazil; and Mr. Bates was obliged to lay trains of gunpowder along their line of march to blow them up, which in the end resulted in scaring the burglars away. We have already alluded to the massive heads possessed by the major and subterranean kinds of neuters, and stated that the work is done by the worker minor or small-headed kind. With regard to the function of the large-headed worker major, Mr. Bates was unable to satisfy himself:

"They are not the soldiers or defenders of the working portion of
the community, like the armed class in the termites, or white ants,
for they never fight. The species has no sting, and does not display
active resistance when interfered with. I once imagined they
exercised a sort of superintendence over the others; but this
function is entirely unnecessary in a community where all work with
a precision and regularity resembling the subordinate parts of a
piece of machinery. I came to the conclusion, at last, that they
have no very precisely defined function. They cannot, however, be
entirely useless to the community, for the sustenance of an idle
class of such bulky individuals would be too heavy a charge for the
species to sustain. I think they serve in some sort as passive
instruments of protection to the real workers. Their enormously
large, hard, and indestructible heads may be of use in protecting
them against the attacks of insectivorous animals. They would be, on
this view, a kind of _pièces de résistance_ serving as a foil
against onslaughts made on the main body of workers."

But the third order, the subterranean kind, we are told, is the most curious of all:

"If the top of a small, fresh hillock, one in which the thatching
process is going on, be taken off, a broad cylindrical shaft is
disclosed, at a depth about two feet from the surface. If this be
probed with a stick, which may be done to the extent of three or
four feet without touching bottom, a small number of colossal
fellows will slowly begin to make their way up the smooth sides of
the mine. Their heads are of the same size as those of the other
class (worker major); but the front is clothed with hairs instead of
being polished, and they have in the middle of the forehead a twin
ocellus, or simple eye, of quite different structure from the
ordinary compound eyes on the side of the head. This frontal eye is
totally wanting in the other workers, and is not known in any other
kind of ant. The apparition of these strange creatures from {188}
the cavernous depths of the mine reminded one, when I first observed
them, of the Cyclopes of Homeric fable. They were not very
pugnacious, as I feared they would be, and I had no difficulty in
securing a few with my fingers. I never saw them under any
circumstances than those here related, and what their special
functions may be I cannot divine."

The naturalist traveller, in the midst of much that interests and delights him, has to put up with a great deal that is annoying, and Mr. Bates proved no exception to the rule. The first few nights when at Caripí, he was much troubled with bats; the room where he slept had not been occupied for several months, and the roof was open to the tiles and rafters:

"On one night," he says, "I was aroused about midnight by the
rushing noise made by vast hosts of bats sweeping about the room.
The air was alive with them; they had put out the lamp, and when I
relighted it, the place appeared blackened with the impish
multitudes that were whirling round and round. After I had lain
about well with a stick for a few minutes they disappeared amongst
the tiles, but when all was still again they returned, and once more
extinguished the light. I took no further notice of them and went to
sleep. The next night several got into my hammock; I seized them as
they were crawling over me, and dashed them against the wall. The
next morning I found a wound, evidently caused by a bat, on my hip."

Bats remind us of the vampire, a native of South America, concerning whose blood-sucking properties so much discussion has been from time to time raised. The vampire bat was very common at Ega; it is the largest of the South American species. Of this bat Mr. Bates writes:

"Nothing in animal physiognomy can be more hideous than the
countenance of this creature when viewed from the front; the large
leathery ears standing out from the sides and top of the head, the
erect, spear-shaped appendage on the tip of the nose, the grin, and
glistening black eyes, all combining to make up a figure that
reminds one of some mocking imp of fable. No wonder that imaginative
people have inferred diabolical instincts on the part of so ugly an
animal. The vampire, however, is the most harmless of all bats, and
its inoffensive character is well known to residents on the banks of
the Amazon."

That much fable has attached itself to the history of this curious creature we are perfectly convinced, and that its blood-sucking peculiarities have been grossly exaggerated we must allow. When this bat has been said to perform the operation of drawing blood "by inserting its aculeated tongue [Footnote 26] into the vein of a sleeping person with so much dexterity as not to be felt, at the same time fanning the air with its large wings, and thus producing a sensation so delightfully cool that the sleep is rendered still more profound," it is clear that the mythical element exists to a great extent in the narrative; but our author's assertion that "the vampire is the most harmless of all bats" does not tally with the statements of other naturalists of considerable note. Mr. Wallace says he saw the effects of the vampire's operations on a young horse, and that the first morning after its arrival the poor animal presented a most pitiable appearance, large streams of clotted blood running down from several wounds on its back and sides:

[Footnote 26: An Expression used by Mr. Wood in his "Zoögraphy.'
It is enough to remark that no known bat has an aculeated.]

"The appearance," Mr. Wallace adds, "was, however, I dare say, worse
than reality, as the bats have the skill to bleed without giving
pain, and it is quite possible the horse, like a patient under the
influence of chloroform, may have known nothing of the matter. The
danger is in the attacks being repeated every night till the loss of
blood becomes serious. To prevent this, red peppers are usually
rubbed {189} on the parts wounded and on all likely places; and this
will partly check the sanguinivorous appetite of the bats, but not
entirely, as in spite of this application the poor animal was again
bitten the next night in fresh places." [Footnote 27]

[Footnote 27: "Travels on the Amazon," p. 44.]

Both Mr. Darwin and Mr. Waterton, if we remember rightly, have borne similar testimony in favor of the opinion that the vampire does suck blood. A servant of the former gentleman, when near Coquimbo, in Chili, observed something attached to the withers of one of his horses, which was restless, and on putting his hand upon the place he secured a vampire bat. Mr. Waterton, however, could not induce the vampires to bite him, notwithstanding the now veteran naturalist [Footnote 28] slept many months in an open loft which the vampires frequented; but an Indian boy who slept near him had his toes often "tapped," while fowls were destroyed, and even an unfortunate donkey was much persecuted, looking, as Mr. Waterton says, "like misery steeped in vinegar."

[Footnote 28: Since this article was in type this excellent
naturalist and kind-hearted gentleman has passed away from amongst
us.]

While at Villa Nova, on the lower Amazons, our naturalist was subjected to another annoyance, in the shape of ticks. The tracts thereabouts "swarmed with carapátos, ugly ticks, belonging to the genus _Ixodes_, which mount to the tops of the blades of grass, and attach themselves to the clothes of passers-by. They are a great annoyance. It occupied me a full hour to pick them off my flesh after my diurnal ramble."

Mr. Bates's stay at Ega, on the upper Amazons, and his expeditions in search of scarlet-faced monkeys, owl-faced night-apes, marmosets, curl-crested toucans, blind ants, and hundreds of other interesting animals, must have been particularly enjoyable, if we except the presence of an abominable gad-fly, which fixes on the flesh of man as breeding-places for its grub, and causes painful tumors. "Ega was a fine field for a natural history collector," and Mr. Bates ticketed with the name of this town more than 3,000 new species of animals.

It is an old and a true saying that you "can have too much of a good thing." A London alderman would soon grumble had he to dine every day on turtle only. "The great fresh-water turtle of the Amazons grows in the upper river to an immense size, a full-grown one measuring nearly three feet in length by two in breadth, and is a load for the strongest Indian. . . . . The flesh is very tender, palatable, and wholesome; but it is very cloying. Every one ends sooner or later by becoming thoroughly surfeited." Our traveller adds that he became so sick of turtle in the course of two years that he could not bear the smell of it, although at the same time nothing else was to be had, and he was suffering actual hunger. The pools about Ega abound in turtles and alligators, and the Indians capture a great number of the former animals by means of sharp steel-pointed arrows, fitted into a peg which enters the tip of the shaft. This peg is fastened to the arrow-shaft by means of a piece of twine; and when the missile--which the people hurl with astonishing skill--pierces the carapace, the peg drops out and the struck turtle dives to the bottom, the detached shaft floating on the surface serving to guide the sportsman to his game. So clever are the natives in the use of the bow and arrow, that they do not wait till the turtle comes to the surface to breathe, but shoot at the back of the animal as it moves under the water, and hardly ever fail to pierce the submerged shell.

One of the most curious and interesting facts in natural history is the assimilation in many animals of form and color to other objects, animate or inanimate. Thus the caterpillars termed, from their mode of progression, "geometric" bear so close a resemblance to the twigs of the trees or bushes upon which they rest that it is no easy thing to distinguish them at a {190} glance; the buff-tip moth, when at rest, looks just like a broken bit of lichen-covered branch, the colored tips of the wings resembling a section of the wood. The beautiful Australian parakeets, known as the Batcherrygar parrots, look so much like the leaves of _Eucalpyti_, or gum-trees, on which they repose, that, though numbers may be perched upon a branch, they are hardly to be seen so long as they keep quiet. Some South American beetles (of the family _Cassidae_) closely resemble glittering drops of dew; some kinds of spiders mimic flower-buds, "and station themselves motionless in the axils of leaves and other parts of plants to wait for their victims." Insects belonging to the genera of _Mantis, Locusta_, and _Phasma_, often show a wonderful resemblance to leaves or sticks. Examples of "mimetic analogy" may also be found amongst birds; but perhaps the most remarkable cases of imitation are to be found among the butterflies of the valley of the Amazon recently made known to us by Mr. Bates. There is a family of butterflies named _Heliconidae_, of a slow flight and feeble structure, very numerous in this South American region, notwithstanding that the districts Abound with insectivorous birds. Now, Mr. Bates has observed that where large numbers of this family are found they are always accompanied by species of a totally distinct family which closely resemble them in size, form, color, and markings. So close is the resemblance that Mr. Bates often found it impossible to distinguish members of one family from those of the other when the insects were on the wing; and he observed, moreover, that when a local variety of a species of the _Heliconidae_ occurred, there was found also a butterfly of another family imitating that local variety. There is no difficulty at all in distinguishing the imitators from the imitated, for the latter have all a family likeness, while the former depart from the normal form and likeness of the families to which they respectively belong. What is the meaning of this curious fact? It is this: the _Heliconidae_, or imitated butterflies, are not persecuted by birds, dragon-flies, lizards, or other insectivorous enemies, while the members of the imitating families are subject to much persecution. The butterflies imitated are said to owe their immunity from persecution to their offensive odor, while no such fortunate character belongs to the imitating insects. But how, we naturally ask, has this change of color and form been effected? Mr. Darwin and Mr. Bates explain it on the principle of natural selection. Let us suppose that a member of the persecuted family gave birth to a variety--and there is a tendency in all animals to produce varieties--exhibiting a very slight resemblance to some species of _Heliconidae_. This individual, in consequence of this slight resemblance, would have a better chance of living and producing young than those of its relatives which bear no resemblance whatever to the unmolested family. Some of the offspring of this slightly favored variety would very probably show more marked resemblance to the unpersecuted butterflies; and thus the likeness between insects of totally distinct groups would in course of time be, according to the law of inheritance, quite complete. This is the explanation which Mr. Bates gives of this natural phenomenon. The phenomenon itself is an undoubted one; whether it is or is not satisfactorily accounted for, cannot at present be determined; we must wait for further investigation.

We had intended to speak of some of the South American palms, those wondrous and valuable productions of tropical countries, the India-rubber trees, and other vegetable productions of the Amazons, but we must linger no longer with the excellent naturalist from whose volumes we have derived so much pleasure. Mr. Bates has written a book full of interest, with the spirit of a real lover of nature and with the pen of a philosopher.

{191}

Leaving, then, the new world, let us cast a glance, in company with one of the greatest botanists of the day, at what we may call the tropical features of the Sikkim Himalayas. Though this region is not strictly speaking within the tropics, yet the vegetation at the base is of a tropical character. In this wonderful district the naturalist is able to wander through every zone of vegetation, from the "dense deep-green dripping forests" at the base of the Himalaya, formed of giant trees, as the _Duabanga_ and _Terminalia_, with _Cedrela_ and _Gordonia Wallichii_, mingled with innumerable shrubs and herbs, to the lichens and mosses of the regions of perpetual snow. The tropical vegetation of the Sikkim extends from Siligoree, a station on the verge of the Terai, "that low malarious belt which skirts the base of the Himalaya from the Sutlej to Brahma-Koond, in Upper Assam."

"Every feature," writes Dr. Hooker, "botanical, geological, and zoological, is new on entering this district. The change is sudden and immediate: sea and shore are hardly more conspicuously different; nor from the edge of the Terai to the limit of perpetual snow is any botanical region more clearly marked than this which is the commencement of Himalayan vegetation." The banks of the numerous tortuous streams are richly clothed with vines and climbing convolvuluses, with various kinds of _Cucurbitaceae_ and _Bignoniaceae_. The district of the Terai is very pestilential, and, though fatal to Europeans, is inhabited by a race called the Mechis with impunity. As our traveller proceeded to the little bungalow of Punkabaree, about 1,800 feet in elevation, the bushy timber of the Terai was found to be replaced by giant forests, with large bamboos cresting the hills, numerous epiphytical orchids and ferns, with _Hoya, Seitamineae_, and similar types of the hottest and dampest climates. All around Punkabaree the hills rise steeply 5,000 or 6,000 feet; from the road at and a little above the bungalow the view is described by Dr. Hooker as superb and very instructive:

"Behind (or north) the Himalaya rise in steep confused masses.
Below, the hill on which I stood, and the ranges as far as the eye
can reach east and west, throw spurs on the plains of India. These
are very thickly wooded, and enclose broad, dead-flat, hot, or damp
valleys, apparently covered with a dense forest. Secondary spurs of
clay and gravel, like that immediately below Punkabaree, rest on the
bases of the mountains and seem to form an intermediate neutral
ground between flat and mountainous India. The Terai district forms
a very irregular belt, scantily clothed, and intersected by
innumerable rivulets from the hills, which unite and divide again on
the flat, till, emerging from the region of many trees, they enter
the plains, following devious courses, which glisten like silver
threads. The whole horizon is bounded by the sea-like expanse of the
plains, which stretch away into the region of sunshine and fine
weather, as one boundless flat. In the distance the courses of the
Teesta and Cosi, the great drainers of the snowy Himalayas, and the
recipients of innumerable smaller rills, are with difficulty traced
at this the dry season. The ocean-like appearance of this southern
view is even more conspicuous in the heavens than on the land, the
clouds arranging themselves after a singularly sea-scape fashion.
Endless strata run in parallel ribbons over the extreme horizon;
above these scattered cumuli, also in horizontal lines, are dotted
against a clear grey sky, which gradually, as the eye is lifted,
passes into a deep cloudless blue vault, continuously clear to the
zenith; there the cumuli, in white fleecy masses, again appear;
till, in the northern celestial hemisphere, they thicken and assume
the leaden hue of nimbi, discharging their moisture on the dark
forest-clad hills around. The breezes are south-easterly, bringing
that {192} vapor from the Indian ocean which is rarefied and
suspended aloft over the heated plains, but condensed into a drizzle
when it strikes the cooler flanks of the hills, and into heavy rain
when it meets their still colder summits. Upon what a gigantic scale
does nature here operate! Vapors raised from an ocean whose nearest
shore is more than 400 miles distant are safely transported without
the loss of one drop of water, to support the rank luxuriance of
this far distant region. This and other offices fulfilled, the waste
waters are returned by the Cosi and Teesta to the ocean, and again
exhaled, exported, expended, recollected, and returned."

Many travellers complain of the annoyance caused to them by leeches. Legions of these pests abound in the water-courses and dense jungles of the Sikkim, and though their bite is painless, it is followed by considerable effusion of blood. "They puncture through thick worsted stockings, and even trousers; and when full roll in the form of a little soft ball into the bottom of the shoe, where their presence is hardly felt in walking."

A thousand feet higher, above the bungalow of Punkabaree, the vegetation is very rich, the prevalent timber being of enormous size, "and scaled by climbing _Leguminosae_, as _Bauhinias_ and _Robinias_, which sometimes sheathe the trunks or span the forest with huge cables, joining tree to tree." Their trunks are also clothed with orchids; and still more beautifully with pothos, peppers, vines, and convolvuli.

"The beauty of the drapery of the pothos leaves (_Scindapsus_) is pre-eminent, whether for the graceful folds the foliage assumes or for the liveliness of its color. Of the more conspicuous smaller trees the wild banana is the most abundant; its crown of very beautiful foliage contrasting with the smaller-leaved plants amongst which it nestles; next comes a screwpine (_Pandanus_) with a straight stem and a tuft of leaves, each eight or ten feet long, waving on all sides. _Araliaceae_, with smooth or armed slender trunks, and _Mappa_-like _Euphorbiaceae_ spread their long petioles horizontally forth, each terminated with an ample leaf some feet in diameter. Bamboo abounds everywhere; its dense tufts of culms, 100 feet and upward high, are as thick as a man's thigh at the base. Twenty or thirty species of ferns (including a tree fern) were luxuriant and handsome. Foliaceous lichens and a few mosses appeared at 2,000 feet. Such is the vegetation of the roads through the tropical forests of Outer Himalaya."

As we ascend about 2,000 feet higher, we find many plants of the temperate zone mingling with the tropical vegetation, amongst which "a very English-looking bramble," bearing a good yellow fruit, is the first to mark the change; next, mighty oaks with large lamellated cups and magnificent foliage succeed, till along the ridge of the mountain to Kursiong, at an elevation of about 4,800 feet, the change in the flora is complete. Here the vegetation recalls to mind home impressions: "the oak flowering, the birch bursting into leaf, the violet, _Chrysosplenium, Stellaria and Arum, Vaccinium_, wild strawberry, maple, geranium, bramble. A colder wind blew here; mosses and lichens carpeted the banks and roadsides; the birds and insects were very different from those below, and everything proclaimed the marked change in the vegetation." And yet even at this elevation we meet with forms of tropical plants, "pothos, bananas, palms, figs, pepper, numbers of epiphytal orchids, and similar genuine tropical genera."

The hill-station of Darjiling, the well-known sanitarium, where the health of Europeans is recruited by a temperate climate, is about 370 miles to the north of Calcutta. The ridge "varies in height from 6,500 to 7,500 feet above the level of the sea, 8,000 feet being the elevation at which the mean temperature most nearly coincides with that of London, viz., 50°." {193} The forests around Darjiling are composed principally of magnolias, oaks, laurels, with birch, alder, maple, holly. Dr. Hooker draws especial attention to the absence of _Leguminosae_, "the most prominent botanical feature in the vegetation of the region," which, he says, is too high for the tropical tribes of the warmer elevation, too low for the Alpines, and probably too moist for those of temperate regions; cool, equable, humid climates being generally unfavorable to the above-named order. "The supremacy of this temperate region consists in the infinite number of forest trees, in the absence (in the usual proportion, at any rate) of such common orders as _Compositae, Leguminosae, Cruciferae_ and _Ranunculaceae_, and of grasses amongst Monocotyledons, and in the predominance of the rarer and more local families, as those of rhododendron, camellia, magnolia, ivy, cornel, honeysuckle, hydrangea, begonia, and epiphytic orchids."

We regret that want of space prevents us dwelling longer on the scenes of tropical Himalaya, so graphically described by Dr. Hooker. We will conclude this imperfect sketch with our traveller's description of the scenery along the banks of the great Rungeet, 6,000 feet below Darjiling:

"Leaving the forest, the path led along the river bank and over the
great masses of rock which strewed its course. The beautiful
India-rubber fig was common. . . . On the forest skirts, _Hoya_,
parasitical _Orchidiae_, and ferns abounded; the Chaulmoogra, whose
fruit is used to intoxicate fish, was very common, as was an immense
mulberry-tree, that yields a milky juice and produces a long, green,
sweet fruit. Large fish, chiefly cyprinoid, were abundant in the
beautifully clear water of the river. But by far the most striking
feature consisted in the amazing quantity of superb butterflies,
large tropical swallow-tails, black, with scarlet or yellow eyes on
their wings. They were seen everywhere, sailing majestically through
the still, hot air, or fluttering from one scorching rock to
another, and especially loving to settle on the damp sand of the
river; where they sat by thousands, with erect wings, balancing
themselves with a rocking motion, as their heavy sails inclined them
to one side or the other, resembling a crowded fleet of yachts on a
calm day. Such an entomological display cannot be surpassed.
_Cicindelae_ and the great _Cicadeae_ were everywhere lighting on
the ground, when they uttered a short sharp creaking sound, and anon
disappeared as if by magic. Beautiful whip-snakes were gleaming in
the sun; they hold on by a few coils of the tall round a twig, the
greater part of their body stretched out horizontally, occasionally
retracting and darting an unerring aim at some insect. The
narrowness of the gorge, and the excessive steepness of the bounding
hills, prevented any view except of the opposite mountain-face,
which was one dense forest, in which the wild banana was
conspicuous."

One of the most remarkable botanical discoveries of modern days is that of a very curious and anomalous genus of plants, named by Dr. Hooker _Welwitschia_ in honor of its discoverer. Dr. Frederic Welwitsch, who first noticed this singular plant in a letter to Sir William Hooker, dated August, 1860. "I have been assured," says Dr. Hooker in his valuable memoir of this plant, "by those who remember it, that since the discovery of the _Rafflesia Arnoldii_, no vegetable production has excited so great an interest as the subject of the present memoir." We well remember this singular plant, having seen a specimen in the Kew Herbarium soon after its arrival in this country. The following is Dr. Hooker's account of its appearance and prominent characters:

"The _Welwitschia_ is a woody plant, said to attain a century in
duration, with an obconic trunk about two feet long, of which a few
inches rise {194} above the soil, presenting the appearance of a
flat, two-lobed depressed mass, sometimes (according to Dr.
Welwitsch) attaining fourteen feet in circumference (!) and looking
like a round table. When full grown, it is dark brown, hard, and
cracked over the whole surface (much like the burnt crust of a loaf
of bread); the lower portion forms a stout tap-root, buried in the
soil and branching downward at the end. From deep grooves in the
circumference of the depressed mass two enormous leaves are given
off, each six feet long when full grown, one corresponding to each
lobe. These are quite flat, linear, very leathery, and split to the
base into innumerable thongs that lie curling upon the surface of
the soil. Its discoverer describes these same two leaves as being
present from the earliest condition of the plant, and assures me
that they are in fact developed from the two cotyledons of the seed,
and are persistent, being replaced by no others. From the
circumference of the tabular mass, above but close to the insertion
of the leaves, spring stout dichotomously branched cymes, nearly a
foot high, bearing small erect scarlet cones, which eventually
become oblong and attain the size of those of the common spruce fir.
The scales of the cones are very closely imbricated, and contain
when young and still very small solitary flowers, which in some
cases are hermaphrodite (structurally but not functionally), in
others female."

After describing these flowers in botanical terms. Dr. Hooker adds, "The mature cone is tetragonous, and contains a broadly winged scale. Its discoverer observes that the whole plant exudes a resin, and that it is called 'tumbo' by the natives. It inhabits the elevated sandy plateau near Cape Negro (lat 14° 40' S. to 23° S.) on the south-west coast of Africa." Dr. Hooker regards the _Welwitschia_ as "the only perennial flowering-plant which at no period has other vegetative organs than those proper to the embryo itself,--the main axis being represented by the radicle, which becomes a gigantic caulicle and develops a root from its base, and inflorescences from its plumulary end, and the leaves being the two cotyledons in a very highly developed and specialized condition." [Footnote 29]

[Footnote 29: "Transactions of the Linnean Society," vol. xxiv.,
part i.]

Few countries present more objects of interest to the naturalist than the island of Madagascar, amongst the botanical treasures of which island the water yam or lace-leaf (_Ouviranidra fenestralis_) claims especial notice. This beautiful and singular plant, which belongs to the natural order _Naiadaceae_, was first made known to the scientific world by du Petit Thouars in 1822. Horticulturists are indebted to Mr. Ellis, the well-known author of "Polynesian Researches," for the introduction of this singular plant into England, specimens of which may be seen in the Royal Gardens at Kew and elsewhere:

"This plant," says Mr. Ellis, "is not only extremely curious, but
also very valuable to the natives, who, at certain seasons of the
year, gather it as an article of food--the fleshy root when cooked
yielding a farinaceous substance resembling the yam. Hence its
native name, _ouvirandrano_, literally, yam of the water;--_ouvi_ in
the Malagasy and Polynesian languages signifying yam, and _rano_ in
the former and some of the latter signifying water. The ouvirandra
is not only a rare and curious, but a singularly beautiful plant,
both in structure and color. From the several crowns of the
branching root, growing often a foot or more deep in the water, a
number of graceful leaves, nine or ten inches long and two or three
inches wide, spread out horizontally just beneath the surface of the
water. The flower-stalks rise from the centre of the leaves, and the
branching or forked flower is curious; but the structure of the leaf
is peculiarly so, and seems like a living fibrous skeleton rather
than an entire leaf. The {195} longitudinal fibres extend in curved
lined along its entire length, and are united by thread-like fibres
or veins, crossing them at right angles from side to side, at a
short distance from each other. The whole leaf looks as if composed
of fine tendrils, wrought after a most regular pattern, so as to
resemble a piece of bright-green lace or open needlework. Each leaf
rises from the crown on the root like a short delicate-looking pale
green or yellow fibre; gradually unfolding its feathery-looking
sides and increasing its size as it spreads beneath the water. The
leaves in their several stages of growth pass through almost every
gradation of color, from a pale yellow to a dark olive-green,
becoming brown or even black before they finally decay; air-bubbles
of considerable size frequently appearing under the full-formed and
healthy leaves. It is scarcely possible to imagine any object of the
kind more attractive and beautiful than a full-grown specimen of
this plant, with its dark green leaves forming the limit of a circle
two or three feet in diameter, and in the transparent water within
that circle presenting leaves in every stage of development, both as
to color and size. Nor is it the least curious to notice that these
slender and fragile structures, apparently not more substantial than
the gossamer and flexible as a feather, still possess a tenacity and
wiriness which allow the delicate leaf to be raised by the hand to
the surface of the water without injury."

No natural order of plants has created or continues to create a greater degree of interest amongst travellers and botanists than the _Orchidaceae_, of which more than three thousand species have been described; the anomalous structure of their reproductory parts, the singularity in form of the floral envelopes, the grotesque resemblance which many kinds bear to some object or other of the animal world, the rarity, beauty, and delicious fragrance of some forms--all combine to render these plants of great value and interest. As inhabitants of hot and damp localities, orchids are in general epiphytes, as in the Brazilian forests, in the lower portions of the Himalayan mountains, and in the islands of the Indian archipelago; when they occur in temperate regions they are terrestrial in their mode of growth; in extremely dry or cold climates, orchidaceous plants are unknown. Two rare and beautiful epiphytal orchids, the _Angraecum sesquipedale_ and _A. superbum_, were obtained by Mr. Ellis in Madagascar and Mauritius, and introduced into this country. Of the former, the largest flowered of all the orchids, Dr. Lindley has given the following description: