The Catholic World Volume Ii Part 28

"This district," he says, "seemed to be an epitome of all that the humid portions of the Para forest could produce. This endless diversity, the coolness of the air, the varied and strange forms of vegetation, the entire freedom from mosquitoes and other pests, and even the solemn gloom and silence, combined to make my rambles through it always pleasant as well as profitable. Such places are paradises to a naturalist, and if he be of a contemplative turn there is no situation more favorable for his indulging the tendency.

There is something in a tropical forest akin to the ocean in its effects on the mind--man feels so completely his insignificance there and the vastness of nature. A naturalist cannot help reflecting on the vegetable forces manifested on so grand a scale around him."

Mr. Wallace and Mr. Bates are well-known advocates of Mr. Darwin's theory of natural selection. The former gentleman was Mr. Bates's companion in travel for four years, and he has published a very interesting account of his voyage on his return to England. Whatever differences of opinion there may be with respect to {182} the celebrated work which Mr. Darwin gave to the world four or five years ago, unbia.s.sed and thoughtful naturalists must recognize the force with which the author supports many of his arguments, and the fairness with which he encounters every difficulty. The compet.i.tion displayed by organized beings is strikingly manifested in the Brazilian forests.

So unmistakable is this fact, that Burmeister, a German traveller, was painfully impressed with the contemplation of the emulation and "spirit of restless selfishness" which the vegetation of a tropical forest displayed. "He thought the softness, earnestness, and repose of European woodland scenery were far more pleasing, and that these formed one of the causes of the superior moral character of European nations;" a curious question, which we leave to the consideration of moral philosophers. The emulation displayed by the plants and trees of the forests of Para is thus spoken of by Mr. Bates:

"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 Para which exhibits this feature in a very prominent manner. It is called the Sipo 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 a.s.sailants. 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, ill.u.s.trating 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 a.s.sociation 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 w.a.n.garoa, 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 compet.i.tion. Although this compet.i.tion 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} s.p.a.ce 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 b.u.t.tress-shaped projections around the lower part of their stems.

The s.p.a.ces between these b.u.t.tresses--which are generally thin walls of wood--form s.p.a.cious 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 b.u.t.tresses, how do they originate, and what is their use? We have already seen how great is the compet.i.tion amongst the trees of a primeval forest, and how every square inch is eagerly battled for by the number of compet.i.tors. 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 compet.i.tion has rendered lateral additions impossible, so these gigantic trees, in order to sustain the ma.s.sive 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 ma.s.s 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 c.u.muli, 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 Coaitas, or spider-monkeys, "as the extreme development of the American type of apes." The flesh of one species of Coaitas 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 Coaitas 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 ma.s.s 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 circ.u.mstance 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 coa.r.s.e 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 circ.u.mstances 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, const.i.tute 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 Sauba, has long been celebrated for its habit of clipping off and carrying away, large quant.i.ties of leaves:

"When employed in this work," Mr. Bates says, "their processions look like a mult.i.tude of animated leaves on the march. In some places I found an acc.u.mulation 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 mult.i.tudes, 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 acc.u.mulates 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 Sauba 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 Sauba 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 ma.s.sive 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 cla.s.s 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 cla.s.s of such bulky individuals would be too heavy a charge for the species to sustain. I think they serve in some sort as pa.s.sive 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 _pieces de resistance_ 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 cla.s.s (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 circ.u.mstances 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 Caripi, 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 mult.i.tudes 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 a.s.sertion 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 "Zoography.'

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 appet.i.te 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 pa.s.sed 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 carapatos, ugly ticks, belonging to the genus _Ixodes_, which mount to the tops of the blades of gra.s.s, and attach themselves to the clothes of pa.s.sers-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 sh.e.l.l.

One of the most curious and interesting facts in natural history is the a.s.similation 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 _Ca.s.sidae_) 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 a.n.a.logy" may also be found amongst birds; but perhaps the most remarkable cases of imitation are to be found among the b.u.t.terflies of the valley of the Amazon recently made known to us by Mr. Bates. There is a family of b.u.t.terflies 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 b.u.t.terfly 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 b.u.t.terflies, 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 b.u.t.terflies 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 b.u.t.terflies; 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.

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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 a.s.sam."

"Every feature," writes Dr. Hooker, "botanical, geological, and zoological, is new on entering this district. The change is sudden and immediate: sea and sh.o.r.e 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: