Amazon and the Maranon, have falls or rapids, either because they
cross the mountains where they take rise, or because they meet other
mountains in their course. If the Amazon, from the pongo of Manseriche
(or, to speak with more precision, from the pongo of Tayuchuc) as far
as its mouth, a space of more than seven hundred and fifty leagues,
exhibit no tumultuous movement of the waters, the river owes this
advantage to the uniform direction of its course. It flows from west
to east in a vast plain, forming a longitudinal valley between the
mountains of Parima and the great mass of the mountains of Brazil.
I was surprised to find by actual measurement that the rapids of the
Orinoco, the roar of which is heard at the distance of more than a
league, and which are so eminently picturesque from the varied
appearance of the waters, the palm-trees and the rocks, have not
probably, on their whole length, a height of more than twenty-eight
feet perpendicular. In reflecting on this, we find that it is a great
deal for rapids, while it would be very little for a single cataract.
The Yellalas of the Rio Congo, in the contracted part of the river
from Banza Noki as far as Banza Inga, furnish, between the upper and
lower levels, a much more considerable difference; but Mr. Barrow
observes, that among the great number of these rapids there is one
fall, which alone is thirty feet high. On the other hand, the famous
pongos of the river Amazon, so dangerous to go up, the falls of
Rentema, of Escurrebragas, and of Mayasi, are but a few feet in
perpendicular height. Those who are engaged in hydraulic works know
the effect that a bar of eighteen or twenty inches' height produces in
a great river. The whirling and tumultuous movement of the water does
not depend solely on the greatness of partial falls; what determines
the force and impetuosity is the nearness of these falls, the
steepness of the rocky ledges, the returning sheets of water which
strike against and surmount each other, the form of the islands and
shoals, the direction of the counter-currents, and the contraction and
sinuosity of the channels through which the waters force a passage
between two adjacent levels. In two rivers equally large, that of
which the falls have least height may sometimes present the greatest
dangers and the most impetuous movements.
It is probable that the river Orinoco loses part of its waters in the
cataracts, not only by increased evaporation, caused by the dispersion
of minute drops in the atmosphere, but still more by filtrations into
the subterraneous cavities. These losses, however, are not very
perceptible when we compare the mass of waters entering into the
raudal with that which issues out near the mouth of the Rio Anaveni.
It was by a similar comparison that the existence of subterraneous
cavities in the yellalas or rapids of the river Congo was discovered.
The pongo of Manseriche, which ought rather to be called a strait than
a fall, ingulfs, in a manner not yet sufficiently explored, a part of
the waters and all the floating wood of the Upper Maranon.
The spectator, seated on the bank of the Orinoco, with his eyes fixed
on those rocky dikes, is naturally led to inquire whether, in the
lapse of ages, the falls change their form or height. I am not much
inclined to believe in such effects of the shock of water against
blocks of granite, and in the erosion of siliceous matter. The holes
narrowed toward the bottom, the funnels that are discovered in the
raudales, as well as near so many other cascades in Europe, are owing
only to the friction of the sand, and the movement of quartz pebbles.
We saw many such, whirled perpetually by the current at the bottom of
the funnels, and contributing to enlarge them in every direction. The
pongos of the river Amazon are easily destroyed, because the rocky
dikes are not granite, but a conglomerate, or red sandstone with large
fragments. A part of the pongo of Rentama was broken down eighty years
ago, and the course of the waters being interrupted by a new bar, the
bed of the river remained dry for some hours, to the great
astonishment of the inhabitants of the village of Payaya, seven
leagues below the pongo. The Indians of Atures assert (and in this
their testimony is contrary to the opinion of Caulin) that the rocks
of the raudal preserve the same aspect; but that the partial torrents
into which the great river divides itself as it passes through the
heaped blocks of granite, change their direction, and carry sometimes
more, sometimes less water towards one or the other bank; but the
causes of these changes may be very remote from the cataracts, for in
the rivers that spread life over the surface of the globe, as in the
arteries by which it is diffused through organized bodies, all the
movements are propagated to great distances. Oscillations, that at
first seem partial, react on the whole liquid mass contained in the
trunk as well as in its numerous ramifications.
Some of the Missionaries in their writings have alleged that the
inhabitants of Atures and Maypures have been struck with deafness by
the noise of the Great Cataracts, but this is untrue. When the noise
is heard in the plain that surrounds the mission, at the distance of
more than a league, you seem to be near a coast skirted by reefs and
breakers. The noise is three times as loud by night as by day, and
gives an inexpressible charm to these solitary scenes. What can be the
cause of this increased intensity of sound, in a desert where nothing
seems to interrupt the silence of nature? The velocity of the
propagation of sound, far from augmenting, decreases with the lowering
of the temperature. The intensity diminishes in air agitated by a wind
which is contrary to the direction of the sound; it diminishes also by
dilatation of the air, and is weaker in the higher than in the lower
regions of the atmosphere, where the number of particles of air in
motion is greater in the same radius. The intensity is the same in dry
air, and in air mingled with vapours; but it is feebler in carbonic
acid gas than in mixtures of azote and oxygen. From these facts, which
are all we know with any certainty, it is difficult to explain a
phenomenon observed near every cascade in Europe, and which, long
before our arrival in the village of Atures, had struck the missionary
and the Indians.
It may be thought that, even in places not inhabited by man, the hum
of insects, the song of birds, the rustling of leaves agitated by the
feeblest winds, occasion during the day a confused noise, which we
perceive the less because it is uniform, and constantly strikes the
ear. Now this noise, however slightly perceptible it may be, may
diminish the intensity of a louder noise; and this diminution may
cease if during the calm of the night the song of birds, the hum of
insects, and the action of the wind upon the leaves be interrupted.
But this reasoning, even admitting its justness, can scarcely be
applied to the forests of the Orinoco, where the air is constantly
filled by an innumerable quantity of mosquitos, where the hum of
insects is much louder by night than by day, and where the breeze, if
ever it be felt, blows only after sunset.
I rather think that the presence of the sun acts upon the propagation
and intensity of sound by the obstacles met in currents of air of
different density, and by the partial undulations of the atmosphere
arising from the unequal heating of different parts of the soil. In
calm air, whether dry or mingled with vesicular vapours equally
distributed, sound-waves are propagated without difficulty. But when
the air is crossed in every direction by small currents of hotter air,
the sonorous undulation is divided into two undulations where the
density of the medium changes abruptly; partial echoes are formed that
weaken the sound, because one of the streams comes back upon itself;
and those divisions of undulations take place of which M. Poisson has
developed the theory with great sagacity.* (* Annales de Chimie tome 7
page 293.) It is not therefore the movement of the particles of air
from below to above in the ascending current, or the small oblique
currents that we consider as opposing by a shock the propagation of
the sonorous undulations. A shock given to the surface of a liquid
will form circles around the centre of percussion, even when the
liquid is agitated. Several kinds of undulations may cross each other
in water, as in air, without being disturbed in their propagation:
little movements may, as it were, ride over each other, and the real
cause of the less intensity of sound during the day appears to be the
interpretation of homogeneity in the elastic medium. During the day
there is a sudden interruption of density wherever small streamlets of
air of a high temperature rise over parts of the soil unequally
heated. The sonorous undulations are divided, as the rays of light are
refracted and form the mirage wherever strata of air of unequal
density are contiguous. The propagation of sound is altered when a
stratum of hydrogen gas is made to rise in a tube closed at one end
above a stratum of atmospheric air; and M. Biot has well explained, by
the interposition of bubbles of carbonic acid gas, why a glass filled
with champagne is not sonorous so long as that gas is evolved, and
passing through the strata of the liquid.
In support of these ideas, I might almost rest on the authority of an
ancient philosopher, whom the moderns do not esteem in proportion to
his merits, though the most distinguished zoologists have long
rendered ample justice to the sagacity of his observations. "Why,"
says Aristotle in his curious book of Problems, "why is sound better
heard during the night? Because there is more calmness on account of
the absence of caloric (of the hottest).* (* I have placed in a
parenthesis, a literal version of the term employed by Aristotle, to
express in reality what we now term the matter of heat. Theodore of
Gaza, in his Latin translation, expresses in the shape of a doubt what
Aristotle positively asserts. I may here remark, that, notwithstanding
the imperfect state of science among the ancients, the works of the
Stagirite contain more ingenious observations than those of many later
philosophers. It is in vain we look in Aristoxenes (De Musica), in
Theophylactus Simocatta (De Quaestionibus physicis), or in the 5th
Book of the Quest. Nat. of Seneca, for an explanation of the nocturnal
augmentation of sound.) This absence renders every thing calmer, for
the sun is the principle of all movement." Aristotle had no doubt a
vague presentiment of the cause of the phenomenon; but he attributes
to the motion of the atmosphere, and the shock of the particles of
air, that which seems to be rather owing to abrupt changes of density
in the contiguous strata of air.
On the 16th of April, towards evening, we received tidings that in
less than six hours our boat had passed the rapids, and had arrived in
good condition in a cove called el Puerto de arriba, or the Port of
the Expedition. We were shown in the little church of Atures some
remains of the ancient wealth of the Jesuits. A silver lamp of
considerable weight lay on the ground half-buried in the sand. Such an
object, it is true, would nowhere tempt the cupidity of a savage; yet
I may here remark, to the honor of the natives of the Orinoco, that
they are not addicted to stealing, like the less savage tribes of the
islands in the Pacific. The former have a great respect for property;
they do not even attempt to steal provision, hooks, or hatchets. At
Maypures and Atures, locks on doors are unknown: they will be
introduced only when whites and men of mixed race establish themselves
in the missions.
The Indians of Atures are mild and moderate, and accustomed, from the
effects of their idleness, to the greatest privations. Formerly, being
excited to labour by the Jesuits, they did not want for food. The
fathers cultivated maize, French beans (frijoles), and other European
vegetables; they even planted sweet oranges and tamarinds round the
villages; and they possessed twenty or thirty thousand head of cows
and horses, in the savannahs of Atures and Carichana. They had at
their service a great number of slaves and servants (peones), to tend
their herds. Nothing is now cultivated but a little cassava, and a few
plantains. Such however is the fertility of the soil, that at Atures I
counted on a single branch of a musa one hundred and eight fruits,
four or five of which would almost have sufficed for a man's daily
food. The culture of maize is entirely neglected, and the horses and
cows have entirely disappeared. Near the raudal, a part of the village
still bears the name of Passo del ganado (ford of the cattle), while
the descendants of those very Indians whom the Jesuits had assembled
in a mission, speak of horned cattle as of animals of a race now lost.
In going up the Orinoco, toward San Carlos del Rio Negro, we saw the
last cow at Carichana. The Fathers of the Observance, who now govern
these vast countries, did not immediately succeed the Jesuits. During
an interregnum of eighteen years, the missions were visited only from
time to time, and by Capuchin monks. The agents of the secular
government, under the title of Royal Commissioners, managed the hatos
or farms of the Jesuits with culpable negligence. They killed the
cattle for the sake of selling the hides. Many heifers were devoured
by the jaguars, and a great number perished in consequence of wounds
made by the bats of the raudales, which, though smaller, are far
bolder than the bats of the Llanos. At the time of the expedition of
the boundaries, horses from Encaramada, Carichana, and Atures, were
conveyed as far as San Jose de Maravitanos, where, on the banks of the
Rio Negro, the Portuguese could only procure them, after a long
passage, and of a very inferior quality, by the rivers Amazon and
Grand Para. Since the year 1795, the cattle of the Jesuits have
entirely disappeared. There now remain as monuments of the ancient
cultivation of these countries, and the active industry of the first
missionaries, only a few trunks of the orange and tamarind, in the
savannahs, surrounded by wild trees.
The tigers, or jaguars, which are less dangerous for the cattle than
the bats, come into the village at Atures, and devour the swine of the
poor Indians. The missionary related to us a striking instance of the
familiarity of these animals, usually so ferocious. Some months before
our arrival, a jaguar, which was thought to be young, though of a
large size, had wounded a child in playing with him. The facts of this
case, which were verified to us on the spot, are not without interest
in the history of the manners of animals. Two Indian children, a boy
and a girl, about eight and nine years of age, were seated on the
grass near the village of Atures, in the middle of a savannah, which
we several times traversed. At two o'clock in the afternoon, a jaguar
issued from the forest, and approached the children, bounding around
them; sometimes he hid himself in the high grass, sometimes he sprang
forward, his back bent, his head hung down, in the manner of our cats.
The little boy, ignorant of his danger, seemed to be sensible of it
only when the jaguar with one of his paws gave him some blows on the
head. These blows, at first slight, became ruder and ruder; the claws
of the jaguar wounded the child, and the blood flowed freely. The
little girl then took a branch of a tree, struck the animal, and it
fled from her. The Indians ran up at the cries of the children, and
saw the jaguar, which then bounded off without making the least show
of resistance.
The little boy was brought to us, who appeared lively and intelligent.
The claw of the jaguar had torn away the skin from the lower part of
the forehead, and there was a second scar at the top of the head. This
was a singular fit of playfulness in an animal which, though not
difficult to be tamed in our menageries, nevertheless shows itself
always wild and ferocious in its natural state. If we admit that,
being sure of its prey, it played with the little Indian as our cats
play with birds whose wings have been clipped, how shall we explain
the patience of a jaguar of large size, which finds itself attacked by
a girl? If the jaguar were not pressed by hunger, why did it approach
the children at all? There is something mysterious in the affections
and hatreds of animals. We have known lions kill three or four dogs
that were put into their den, and instantly caress a fifth, which,
less timid, took the king of animals by the mane. These are instincts
of which we know not the secret.
We have mentioned that domestic pigs are attacked by the jaguars.
There are in these countries, besides the common swine of European
race, several species of peccaries, or pigs with lumbar glands, two of
which only are known to the naturalists of Europe. The Indians call
the little peccary (Dicotiles torquatus, Cuv.), in the Maypure tongue,
chacharo; while they give the name of apida to a species of pig which
they say has no pouch, is larger, and of a dark brown colour, with the
belly and lower jaw white. The chacharo, reared in the houses, becomes
tame like our sheep and goats. It reminds us, by the gentleness of its
manners, of the curious analogies which anatomists have observed
between the peccaries and the ruminating animals. The apida, which is
domesticated like our swine in Europe, wanders in large herds composed
of several hundreds. The presence of these herds is announced from
afar, not only by their hoarse gruntings, but above all by the
impetuosity with which they break down the shrubs in their way. M.
Bonpland, in an herborizing excursion, warned by his Indian guide to
hide himself behind the trunk of a tree, saw a number of these
peccaries (cochinos or puercos del monte) pass close by him. The herd
marched in a close body, the males proceeding first; and each sow was
accompanied by her young. The flesh of the chacharo is flabby, and not
very agreeable; it affords, however, a plentiful nourishment to the
natives, who kill these animals with small lances tied to cords. We
were assured at Atures, that the tiger dreads being surrounded in the
forests by these herds of wild pigs; and that, to avoid being stifled,
he tries to save himself by climbing up a tree. Is this a hunter's
tale, or a fact that has really been observed? In several parts of
America the hunters believe in the existence of a javali, or native
boar with tusks curved outwardly. I never saw one, but this animal is
mentioned in the works of the Spanish missionaries, a source too much
neglected by zoologists; for amidst much incorrectness and
extravagance, they contain many curious local observations.
Among the monkeys which we saw at the mission of the Atures, we found
one new species, of the tribe of sais and sajous, which the Creoles
vulgarly call machis. It is the Guvapavi with grey hair and a bluish
face. It has the orbits of the eyes and the forehead as white as snow,
a peculiarity which at first sight distinguishes it from the Simia
capucina, the Simia apella, the Simia trepida, and the other weeping
monkeys hitherto so confusedly described. This little animal is as
gentle as it is ugly. A monkey of this species, which was kept in the
courtyard of the missionary, would frequently mount on the back of a
pig, and in this manner traverse the savannahs. We have also seen it
upon the back of a large cat, which had been brought up with it in
Father Zea's house.
It was among the cataracts that we began to hear of the hairy man of
the woods, called salvaje, that carries off women, constructs huts,
and sometimes eats human flesh. The Tamanacs call it achi, and the
Maypures vasitri, or great devil. The natives and the missionaries
have no doubt of the existence of this man-shaped monkey, of which
they entertain a singular dread. Father Gili gravely relates the
history of a lady in the town of San Carlos, in the Llanos of
Venezuela, who much praised the gentle character and attentions of the
man of the woods. She is stated to have lived several years with one
in great domestic harmony, and only requested some hunters to take her
back, because she and her children (a little hairy also) were weary of
living far from the church and the sacraments. The same author,
notwithstanding his credulity, acknowledges that he never knew an
Indian who asserted positively that he had seen the salvaje with his
own eyes. This wild legend, which the missionaries, the European
planters, and the negroes of Africa, have no doubt embellished with
many features taken from the description of the manners of the
orang-otang,* the gibbon, the jocko or chimpanzee, and the pongo,
followed us, during five years, from the northern to the southern
hemisphere. (* Simia satyrus. We must not believe, notwithstanding the
assertions of almost all zoological writers, that the word orang-otang
is applied exclusively in the Malay language to the Simia satyrus of
Borneo. This expression, on the contrary, means any very large monkey,
that resembles man in figure. Marsden's History of Sumatra 3rd edition
page 117. Modern zoologists have arbitrarily appropriated provincial
names to certain species; and by continuing to prefer these names,
strangely disfigured in their orthography, to the Latin systematic
names, the confusion of the nomenclature has been increased.) We were
everywhere blamed, in the most cultivated class of society, for being
the only persons to doubt the existence of the great anthropomorphous
monkey of America. There are certain regions where this belief is
particularly prevalent among the people; such are the banks of the
Upper Orinoco, the valley of Upar near the lake of Maracaybo, the
mountains of Santa Martha and of Merida, the provinces of Quixos, and
the banks of the Amazon near Tomependa. In all these places, so
distant one from the other, it is asserted that the salvaje is easily
recognized by the traces of its feet, the toes of which are turned
backward. But if there exist a monkey of a large size in the New
Continent, how has it happened that for three centuries no man worthy
of belief has been able to procure the skin of one? Several hypotheses
present themselves to the mind, in order to explain the source of so
ancient an error or belief. Has the famous capuchin monkey of
Esmeralda (Simia chiropotes), with its long canine teeth, and
physiognomy much more like man's* (* The whole of the features--the
expression of the physiognomy; but not the forehead.) than that of the
orang-otang, given rise to the fable of the salvaje? It is not so
large indeed as the coaita (Simia paniscus); but when seen at the top
of a tree, and the head only visible, it might easily be taken for a
human being. It may be also (and this opinion appears to me the most
probable) that the man of the woods was one of those large bears, the
footsteps of which resemble those of a man, and which are believed in
every country to attack women. The animal killed in my time at the
foot of the mountains of Merida, and sent, by the name of salvaje, to
Colonel Ungaro, the governor of the province of Varinas, was in fact a
bear with black and smooth fur. Our fellow-traveller, Don Nicolas
Soto, had examined it closely. Did the strange idea of a plantigrade
animal, the toes of which are placed as if it walked backward, take
its origin from the habit of the real savages of the woods, the
Indians of the weakest and most timid tribes, of deceiving their
enemies, when they enter a forest, or cross a sandy shore, by covering
the traces of their feet with sand, or walking backward?
Though I have expressed my doubts of the existence of an unknown
species of large monkey in a continent which appears entirely
destitute of quadrumanous animals of the family of the orangs,
cynocephali, mandrils, and pongos; yet it should be remembered that
almost all matters of popular belief, even those most absurd in
appearance, rest on real facts, but facts ill observed. In treating
them with disdain, the traces of a discovery may often be lost, in
natural philosophy as well as in zoology. We will not then admit, with
a Spanish author, that the fable of the man of the woods was invented
by the artifice of Indian women, who pretended to have been carried
off, when they had been long absent unknown to their husbands.
Travellers who may hereafter visit the missions of the Orinoco will do
well to follow up our researches on the salvaje or great devil of the
woods; and examine whether it be some unknown species of bear, or some
very rare monkey analogous to the Simia chiropotes, or Simia satanas,
which may have given rise to such singular tales.
After having spent two days near the cataract of Atures, we were not
sorry when our boat was reladen, and we were enabled to leave a spot
where the temperature of the air is generally by day twenty-nine
degrees, and by night twenty-six degrees, of the centigrade
thermometer. This temperature seemed to us to be still much more
elevated, from the feeling of heat which we experienced. The want of
concordance between the instruments and the sensations must be
attributed to the continual irritation of the skin excited by the
mosquitos. An atmosphere filled with venomous insects always appears
to be more heated than it is in reality. We were horribly tormented in
the day by mosquitos and the jejen, a small venomous fly (simulium),
and at night by the zancudos, a large species of gnat, dreaded even by
the natives. Our hands began to swell considerably, and this swelling
increased daily till our arrival on the banks of the Temi. The means
that are employed to escape from these little plagues are very
extraordinary. The good missionary Bernardo Zea, who passed his life
tormented by mosquitos, had constructed near the church, on a
scaffolding of trunks of palm-trees, a small apartment, in which we
breathed more freely. To this we went up in the evening, by means of a
ladder, to dry our plants and write our journal. The missionary had
justly observed, that the insects abounded more particularly in the
lowest strata of the atmosphere, that which reaches from the ground to
the height of twelve or fifteen feet. At Maypures the Indians quit the
village at night, to go and sleep on the little islets in the midst of
the cataracts. There they enjoy some rest; the mosquitoes appearing to
shun air loaded with vapours. We found everywhere fewer in the middle
of the river than near its banks; and thus less is suffered in
descending the Orinoco than in going up in a boat.
Persons who have not navigated the great rivers of equinoctial
America, for instance, the Orinoco and the Magdalena, can scarcely
conceive how, at every instant, without intermission, you may be
tormented by insects flying in the air; and how the multitude of these
little animals may render vast regions almost uninhabitable. Whatever
fortitude be exercised to endure pain without complaint, whatever
interest may be felt in the objects of scientific research, it is
impossible not to be constantly disturbed by the mosquitos, zancudos,
jejens, and tempraneros, that cover the face and hands, pierce the
clothes with their long needle-formed suckers, and getting into the
mouth and nostrils, occasion coughing and sneezing whenever any
attempt is made to speak in the open air. In the missions of the
Orinoco, in the villages on the banks of the river, surrounded by
immense forests, the plaga de las moscas, or the plague of the
mosquitos, affords an inexhaustible subject of conversation. When two
persons meet in the morning, the first questions they address to each
other are: How did you find the zancudos during the night? How are we
to-day for the mosquitos?* (* Que le han parecido los zancudos de
noche? Como stamos hoy de mosquitos?) These questions remind us of a
Chinese form of politeness, which indicates the ancient state of the
country where it took birth. Salutations were made heretofore in the
Celestial empire in the following words, vou-to-hou, Have you been
incommoded in the night by the serpents?
The geographical distribution of the insects of the family of tipulae
presents very remarkable phenomena. It does not appear to depend
solely on heat of climate, excess of humidity, or the thickness of
forests, but on local circumstances that are difficult to
characterise. It may be observed that the plague of mosquitos and
zancudos is not so general in the torrid zone as is commonly believed.
On the table-lands elevated more than four hundred toises above the
level of the ocean, in the very dry plains remote from the beds of
great rivers (for instance, at Cumana and Calabozo), there are not
sensibly more gnats than in the most populous parts of Europe. They
are perceived to augment enormously at Nueva Barcelona, and more to
the west, on the coast that extends towards Cape Codera. Between the
little harbour of Higuerote and the mouth of the Rio Unare, the
wretched inhabitants are accustomed to stretch themselves on the
ground, and pass the night buried in the sand three or four inches
deep, leaving out the head only, which they cover with a handkerchief.
You suffer from the sting of insects, but in a manner easy to bear, in
descending the Orinoco from Cabruta towards Angostura, and in going up
from Cabruta towards Uruana, between the latitudes of 7 and 8 degrees.
But beyond the mouth of the Rio Arauca, after having passed the strait
of Baraguan, the scene suddenly changes. From this spot the traveller
may bid farewell to repose. If he have any poetical remembrance of
Dante, he may easily imagine he has entered the citta dolente, and he
will seem to read on the granite rocks of Baraguan these lines of the
Inferno:
Noi sem venuti al luogo, ov' i' t'ho detto
Che tu vedrai le genti dolorose.
The lower strata of air, from the surface of the ground to the height
of fifteen or twenty feet, are absolutely filled with venomous
insects. If in an obscure spot, for instance in the grottos of the
cataracts formed by superincumbent blocks of granite, you direct your
eyes toward the opening enlightened by the sun, you see clouds of
mosquitos more or less thick. At the mission of San Borja, the
suffering from mosquitos is greater than at Carichana; but in the
Raudales, at Atures, and above all at Maypures, this suffering may be
said to attain its maximum. I doubt whether there be a country upon
earth where man is exposed to more cruel torments in the rainy season.
Having passed the fifth degree of latitude, you are somewhat less
stung; but on the Upper Orinoco the stings are more painful, because
the heat and the absolute want of wind render the air more burning and
more irritating in its contact with the skin.
"How comfortable must people be in the moon!" said a Salive Indian to
Father Gumilla; "she looks so beautiful and so clear, that she must be
free from mosquitos." These words, which denote the infancy of a
people, are very remarkable. The satellite of the earth appears to all
savage nations the abode of the blessed, the country of abundance. The
Esquimaux, who counts among his riches a plank or trunk of a tree,
thrown by the currents on a coast destitute of vegetation, sees in the
moon plains covered with forests; the Indian of the forests of Orinoco
there beholds open savannahs, where the inhabitants are never stung by
mosquitos.
After proceeding further to the south, where the system of
yellowish-brown waters commences,* (* Generally called black waters,
aguas negras.) on the banks of the Atabapo, the Tuni, the Tuamini, and
the Rio Negro, we enjoyed an unexpected repose. These rivers, like the
Orinoco, cross thick forests, but the tipulary insects, as well as the
crocodiles, shun the proximity of the black waters. Possibly these
waters, which are a little colder, and chemically different from the
white waters, are adverse to the larvae of tipulary insects and gnats,
which may be considered as real aquatic animals. Some small rivers,
the colour of which is deep blue, or yellowish-brown (as the Toparo,
the Mataveni, and the Zama), are exceptions to the almost general rule
of the absence of mosquitos over the black waters. These three rivers
swarm with them; and the Indians themselves fixed our attention on the
problematic causes of this phenomenon. In going down the Rio Negro, we
breathed freely at Maroa, Daripe, and San Carlos, villages situated on
the boundaries of Brazil. But this improvement of our situation was of
short continuance; our sufferings recommenced as soon as we entered
the Cassiquiare. At Esmeralda, at the eastern extremity of the Upper
Orinoco, where ends the known world of the Spaniards, the clouds of
mosquitos are almost as thick as at the Great Cataracts. At Mandavaca
we found an old missionary, who told us with an air of sadness, that
he had had his twenty years of mosquitos in America*. (* "Yo tengo mis
veinte anos de mosquitos.") He desired us to look at his legs, that we
might be able to tell one day, beyond sea (por alla), what the poor
monks suffer in the forests of Cassiquiare. Every sting leaving a
small darkish brown point, his legs were so speckled that it was
difficult to recognize the whiteness of his skin through the spots of
coagulated blood. If the insects of the genus Simulium abound in the
Cassiquiare, which has white waters, the culices or zancudos are so
much the more rare; you scarcely find any there; while on the rivers
of black waters, in the Atabapo and the Rio, there are generally some
zancudos and no mosquitos.
I have just shown, from my own observations, how much the geographical
distribution of venomous insects varies in this labyrinth of rivers
with white and black waters. It were to be wished that a learned
entomologist could study on the spot the specific differences of these
noxious insects,* which in the torrid zone, in spite of their minute
size, act an important point in the economy of nature. (* The mosquito
bovo or tenbiguai; the melero, which always settles upon the eyes; the
tempranero, or putchiki; the jejen; the gnat rivau, the great zancudo,
or matchaki; the cafafi, etc.) What appeared to us very remarkable,
and is a fact known to all the missionaries, is, that the different
species do not associate together, and that at different hours of the
day you are stung by distinct species. Every time that the scene
changes, and, to use the simple expression of the missionaries, other
insects mount guard, you have a few minutes, often a quarter of an
hour, of repose. The insects that disappear have not their places
instantly supplied by their successors. From half-past-six in the
morning till five in the afternoon, the air is filled with mosquitos;
which have not, as some travellers have stated, the form of our
gnats,* (* Culex pipiens. This difference between mosquito (little
fly, simulium) and zancudo (gnat, culex) exists in all the Spanish
colonies. The word zancudo signifies long legs, qui tiene las zancas
largas. The mosquitos of the Orinoco are the moustiques; the zancudos
are the maringouins of French travellers.) but that of a small fly.
They are simuliums of the family Nemocera of the system of Latreille.
Their sting is as painful as that of the genus Stomox. It leaves a
little reddish brown spot, which is extravased and coagulated blood,
where their proboscis has pierced the skin. An hour before sunset a
species of small gnats, called tempraneros,* because they appear also
at sunrise, take the place of the mosquitos. (* Which appear at an
early hour (temprano). Some persons say, that the zancudo is the same
as the tempranero, which returns at night, after hiding itself for
some time. I have doubts of this identity of the species; the pain
caused by the sting of the two insects appeared to me different.)
Their presence scarcely lasts an hour and a half; they disappear
between six and seven in the evening, or, as they say here, after the
Angelus (a la oracion). After a few minutes' repose, you feel yourself
stung by zancudos, another species of gnat with very long legs. The
zancudo, the proboscis of which contains a sharp-pointed sucker,
causes the most acute pain, and a swelling that remains several weeks.
Its hum resembles that of the European gnat, but is louder and more
prolonged. The Indians pretend to distinguish the zancudos and the
tempraneros by their song; the latter are real twilight insects, while
the zancudos are most frequently nocturnal insects, and disappear
toward sunrise.
In our way from Carthagena to Santa Fe de Bogota, we observed that
between Mompox and Honda, in the valley of the Rio Magdalena, the
zancudos darkened the air from eight in the evening till midnight;
that towards midnight they diminished in number, and were hidden for
three or four hours; and lastly that they returned in crowds, about
four in the morning. What is the cause of these alternations of motion
and rest? Are these animals fatigued by long flight? It is rare on the
Orinoco to see real gnats by day; while at the Rio Magdalena we were
stung night and day, except from noon till about two o'clock. The
zancudos of the two rivers are no doubt of different species.
We have seen that the insects of the tropics everywhere follow a
certain standard in the periods at which they alternately arrive and
disappear. At fixed and invariable hours, in the same season, and the
same latitude, the air is peopled with new inhabitants, and in a zone
where the barometer becomes a clock,* (* By the extreme regularity of
the horary variations of the atmospheric pressure.) where everything
proceeds with such admirable regularity, we might guess blindfold the
hour of the day or night, by the hum of the insects, and by their
stings, the pain of which differs according to the nature of the
poison that each species deposits in the wound.
At a period when the geography of animals and of plants had not yet
been studied, the analogous species of different climates were often
confounded. It was believed that the pines and ranunculuses, the
stags, the rats, and the tipulary insects of the north of Europe, were
to be found in Japan, on the ridge of the Andes, and at the Straits of
Magellan. Justly celebrated naturalists have thought that the zancudo
of the torrid zone was the gnat of our marshes, become more vigorous,
more voracious, and more noxious, under the influence of a burning
climate. This is a very erroneous opinion. I carefully examined and
described upon the spot those zancudos, the stings of which are most
tormenting. In the rivers Magdalena and Guayaquil alone there are five
distinct species.
The culices of South America have generally the wings, corslet, and
legs of an azure colour, ringed and variegated with a mixture of spots
of metallic lustre. Here as in Europe, the males, which are
distinguished by their feathered antennae, are extremely rare; you are
seldom stung except by females. The preponderance of this sex explains
the immense increase of the species, each female laying several
hundred eggs. In going up one of the great rivers of America, it is
observed, that the appearance of a new species of culex denotes the
proximity of a new stream flowing in. I shall mention an instance of
this curious phenomenon. The Culex lineatus, which belongs to the Cano
Tamalamec, is only perceived in the valley of the Rio Grande de la
Magdalena, at a league north of the junction of the two rivers; it
goes up, but scarcely ever descends the Rio Grande. It is thus, that,
on a principal vein, the appearance of a new substance in the gangue
indicates to the miner the neighbourhood of a secondary vein that
joins the first.
On recapitulating the observations here recorded, we see, that within
the tropics, the mosquitos and zancudos do not rise on the slope of
the Cordilleras* toward the temperate region, where the mean heat is
below 19 or 20 degrees (* The culex pipiens of Europe does not, like
the culex of the torrid zone, shun mountainous places. Giesecke
suffered from these insects in Greenland, at Disco, in latitude 70
degrees. They are found in Lapland in summer, at three or four hundred
toises high, and at a temperature of 11 or 12 degrees.); and that,
with few exceptions, they shun the black waters, and dry and unwooded
spots.* (* Trifling modifications in the waters, or in the air, often
appear to prevent the development of the mosquitos. Mr. Bowdich
remarks that there are none at Coomassie, in the kingdom of the
Ashantees, though the town is surrounded by marshes, and though the
thermometer keeps up between seventeen and twenty-eight centesimal
degrees, day and night.) The atmosphere swarms with them much more in
the Upper than in the Lower Orinoco, because in the former the river
is surrounded with thick forests on its banks, and the skirts of the
forests are not separated from the river by a barren and extensive
beach. The mosquitos diminish on the New Continent with the diminution
of the water, and the destruction of the woods; but the effects of
these changes are as slow as the progress of cultivation. The towns of
Angostura, Nueva Barcelona, and Mompox, where from the want of police,
the streets, the great squares, and the interior of court-yards are
overgrown with brushwood, are sadly celebrated for the abundance of
zancudos.
People born in the country, whether whites, mulattoes, negroes, or
Indians, all suffer from the sting of these insects. But as cold does
not render the north of Europe uninhabitable, so the mosquitos do not
prevent men from dwelling in the countries where they abound, provided
that, by their situation and government, they afford resources for
agriculture and industry. The inhabitants pass their lives in
complaining of the insufferable torment of the mosquitos, yet,
notwithstanding these continual complaints, they seek, and even with a
sort of predilection, the commercial towns of Mompox, Santa Marta, and
Rio de la Hacha. Such is the force of habit in evils which we suffer
every hour of the day, that the three missions of San Borja, Atures,
and Esmeralda, where, to make use of an hyperbolical expression of the
monks, there are more mosquitos than air,* (* Mas moscas que aire.)
would no doubt become flourishing towns, if the Orinoco afforded
planters the same advantages for the exchange of produce, as the Ohio
and the Lower Mississippi.
It is a curious fact, that the whites born in the torrid zone may walk
barefoot with impunity, in the same apartment where a European
recently landed is exposed to the attack of the nigua or chegoe (Pulex
penetrans). This animal, almost invisible to the eye, gets under the
toe-nails, and there acquires the size of a small pea, by the quick
increase of its eggs, which are placed in a bag under the belly of the
insect. The nigua therefore distinguishes what the most delicate
chemical analysis could not distinguish, the cellular membrane and
blood of a European from those of a creole white. The mosquitos, on
the contrary, attack equally the natives and the Europeans; but the
effects of the sting are different in the two races of men. The same
venomous liquid, deposited in the skin of a copper-coloured man of
Indian race, and in that of a white man newly landed, causes no
swelling in the former, while in the latter it produces hard blisters,
greatly inflamed, and painful for several days; so different is the
action on the epidermis, according to the degree of irritability of
the organs in different races and different individuals!
I shall here recite several facts, which prove that the Indians, and
in general all the people of colour, at the moment of being stung,
suffer like the whites, although perhaps with less intensity of pain.
In the day-time, and even when labouring at the oar, the natives, in
order to chase the insects, are continually giving one another smart
slaps with the palm of the hand. They even strike themselves and their
comrades mechanically during their sleep. The violence of their blows
reminds one of the Persian tale of the bear that tried to kill with
his paw the insects on the forehead of his sleeping master. Near
Maypures we saw some young Indians seated in a circle and rubbing
cruelly each others' backs with the bark of trees dried at the fire.
Indian women were occupied, with a degree of patience of which the
copper-coloured race alone are capable, in extracting, by means of a
sharp bone, the little mass of coagulated blood that forms the centre
of every sting, and gives the skin a speckled appearance. One of the
most barbarous nations of the Orinoco, that of the Ottomacs, is
acquainted with the use of mosquito-curtains (mosquiteros) woven from
the fibres of the moriche palm-tree. At Higuerote, on the coast of
Caracas, the copper-coloured people sleep buried in the sand. In the
villages of the Rio Magdalena the Indians often invited us to stretch
ourselves as they did on ox-skins, near the church, in the middle of
the plaza grande, where they had assembled all the cows in the
neighbourhood. The proximity of cattle gives some repose to man. The
Indians of the Upper Orinoco and the Cassiquiare, seeing that M.
Bonpland could not prepare his herbal, owing to the continual torment
of the mosquitos, invited him to enter their ovens (hornitos). Thus
they call little chambers, without doors or windows, into which they
creep horizontally through a very low opening. When they have driven
away the insects by means of a fire of wet brushwood, which emits a
great deal of smoke, they close the opening of the oven. The absence
of the mosquitos is purchased dearly enough by the excessive heat of
the stagnated air, and the smoke of a torch of copal, which lights the
oven during your stay in it. M. Bonpland, with courage and patience
well worthy of praise, dried hundreds of plants, shut up in these
hornitos of the Indians.
These precautions of the Indians sufficiently prove that,
notwithstanding the different organization of the epidermis, the
copper-coloured man, like the white man, suffers from the stings of
insects; but the former seems to feel less pain, and the sting is not
followed by those swellings which, during several weeks, heighten the
irritability of the skin, and throw persons of a delicate constitution
into that feverish state which always accompanies eruptive maladies.
Whites born in equinoctial America, and Europeans who have long
sojourned in the Missions, on the borders of forests and great rivers,
suffer much more than the Indians, but infinitely less than Europeans
newly arrived. It is not, therefore, as some travellers assert, the
thickness of the skin that renders the sting more or less painful at
the moment when it is received; nor is it owing to the particular
organization of the integuments, that in the Indians the sting is
followed by less of swelling and inflammatory symptoms; it is on the
nervous irritability of the epidermis that the acuteness and duration
of the pain depend. This irritability is augmented by very warm
clothing, by the use of alcoholic liquors, by the habit of scratching
the wounds, and lastly, (and this physiological observation is the
result of my own experience,) that of baths repeated at too short
intervals. In places where the absence of crocodiles permits people to
enter a river, M. Bonpland and myself observed that the immoderate use
of baths, while it moderated the pain of old stings of zancudos,
rendered us more sensible to new stings. By bathing more than twice a
day, the skin is brought into a state of nervous irritability, of
which no idea can be formed in Europe. It would seem as if all feeling
were carried toward the integuments.
As the mosquitos and gnats pass two-thirds of their lives in the
water, it is not surprising that these noxious insects become less
numerous in proportion as you recede from the banks of the great
rivers which intersect the forests. They seem to prefer the spots
where their metamorphosis took place, and where they go to deposit
their eggs. In fact the wild Indians (Indios monteros) experience the
greater difficulty in accustoming themselves to the life of the
missions, as they suffer in the Christian establishments a torment
which they scarcely know in their own inland dwellings. The natives at
Maypures, Atures, and Esmeralda, have been seen fleeing to the woods,
or, as they say, al monte, solely from the dread of mosquitos.
Unfortunately, all the Missions of the Orinoco have been established
too near the banks of the river. At Esmeralda the inhabitants assured
us that if the village were situated in one of the five plains
surrounding the high mountains of Duida and Maraguaca, they should
breathe freely, and enjoy some repose. The great cloud of mosquitos
(la nube de moscas) to use the expression of the monks, is suspended
only over the Orinoco and its tributary streams, and is dissipated in
proportion as you remove from the rivers. We should form a very
inaccurate idea of Guiana and Brazil, were we to judge of that great
forest four hundred leagues wide, lying between the sources of the
Madeira and the Lower Orinoco, from the valleys of the rivers by which
it is crossed.
I learned that the little insects of the family of the nemocerae
migrate from time to time like the alouate monkeys, which live in
society. In certain spots, at the commencement of the rainy season,
different species appear, the sting of which has not yet been felt. We
were informed at the Rio Magdalena, that at Simiti no other culex than
the jejen was formerly known; and it was then possible to enjoy a
tranquil night's rest, for the jejen is not a nocturnal insect. Since
the year 1801, the great blue-winged gnat (Culex cyanopterus) has
appeared in such numbers, that the poor inhabitants of Simiti know not
how to procure an undisturbed sleep. In the marshy channels (esteros)
of the isle of Baru, near Carthagena, is found a little white fly
called cafafi. It is scarcely visible to the naked eye, and causes
very painful swellings. The toldos or cottons used for
mosquito-curtains, are wetted to prevent the cafafi penetrating
through the interstices left by the crossing threads. This insect,
happily rare elsewhere, goes up in January, by the channel (dique) of
Mahates, as far as Morales. When we went to this village in the month
of May, we found there cimuliae and zancudos, but no jejens.
The insects most troublesome at Orinoco, or as the Creoles say, the
most ferocious (los mas feroces), are those of the great cataracts of
Esmeralda and Mandavaca. On the Rio Magdalena the Culex cyanopterus is
dreaded, particularly at Mompox, Chiloa, and Tamalameca. At these
places this insect is larger and stronger, and its legs blacker. It is
difficult to avoid smiling on hearing the missionaries dispute about
the size and voracity of the mosquitos at different parts of the same
river. In a region the inhabitants of which are ignorant of all that
is passing in the rest of the world, this is the favourite subject of
conversation. "How I pity your situation!" said the missionary of the
Raudales to the missionary of Cassiquiare, at our departure; "you are
alone, like me, in this country of tigers and monkeys; with you fish
is still more rare, and the heat more violent; but as for my mosquitos
(mias moscas) I can boast that with one of mine I would beat three of
yours."
This voracity of insects in certain spots, the fury with which they
attack man,* (* This voracity, this appetite for blood, seems
surprising in little insects, that live on vegetable juices, and in a
country almost entirely uninhabited. "What would these animals eat, if
we did not pass this way?" say the Creoles, in going through countries
where there are only crocodiles covered with a scaly skin, and hairy
monkeys.) the activity of the venom varying in the same species, are
very remarkable facts; which find their analogy, however, in the
classes of large animals. The crocodile of Angostura pursues men,
while at Nueva Barcelona you may bathe tranquilly in the Rio Neveri
amidst these carnivorous reptiles. The jaguars of Maturin, Cumanacoa,
and the isthmus of Panama, are timid in comparison of those of the
Upper Orinoco. The Indians well know that the monkeys of some valleys
are easily tamed, while others of the same species, caught elsewhere,
will rather die of hunger than submit to slavery.* (* I might have
added the example of the scorpion of Cumana, which it is very
difficult to distinguish from that of the island of Trinidad, Jamaica,
Carthagena, and Guayaquil; yet the former is not more to be feared
than the Scorpio europaeus (of the south of France), while the latter
produces consequences far more alarming than the Scorpio occitanus (of
Spain and Barbary). At Carthagena and Guayaquil, the sting of the
scorpion (alacran) instantly causes the loss of speech. Sometimes a
singular torpor of the tongue is observed for fifteen or sixteen
hours. The patient, when stung in the legs, stammers as if he had been
struck with apoplexy.)
The common people in America have framed systems respecting the
salubrity of climates and pathological phenomena, as well as the
learned of Europe; and their systems, like ours, are diametrically
opposed to each other, according to the provinces into which the New
Continent is divided. At the Rio Magdalena the frequency of mosquitos
is regarded as troublesome, but salutary. These animals, say the
inhabitants, give us slight bleedings, and preserve us, in a country
excessively hot, from the scarlet fever, and other inflammatory
diseases. But at the Orinoco, the banks of which are very
insalubrious, the sick blame the mosquitos for all their sufferings.
It is unnecessary to refute the fallacy of the popular belief that the
action of the mosquitos is salutary by its local bleedings. In Europe
the inhabitants of marshy countries are not ignorant that the insects
irritate the epidermis, and stimulate its functions by the venom which
they deposit in the wounds they make. Far from diminishing the
inflammatory state of the skin, the stings increase it.
The frequency of gnats and mosquitos characterises unhealthy climates
only so far as the development and multiplication of these insects
depend on the same causes that give rise to miasmata. These noxious
animals love a fertile soil covered with plants, stagnant waters, and
a humid air never agitated by the wind; they prefer to an open country
those shades, that softened day, that tempered degree of light, heat,
and moisture which, while it favours the action of chemical
affinities, accelerates the putrefaction of organised substances. May
not the mosquitos themselves increase the insalubrity of the
atmosphere? When we reflect that to the height of three or four toises
a cubic foot of air is often peopled by a million of winged insects,*
(* It is sufficient to mention, that the cubic foot contains 2,985,984
cubic lines.) which contain a caustic and venomous liquid; when we
recollect that several species of culex are 1.8 lines long from the
head to the extremity of the corslet (without reckoning the legs);
lastly, when we consider that in this swarm of mosquitos and gnats,
diffused in the atmosphere like smoke, there is a great number of dead
insects raised by the force of the ascending air, or by that of the
lateral currents which are caused by the unequal heating of the soil,
we are led to inquire whether the presence of so many animal
substances in the air must not occasion particular miasmata. I think
that these substances act on the atmosphere differently from sand and
dust; but it will be prudent to affirm nothing positively on this
subject. Chemistry has not yet unveiled the numerous mysteries of the
insalubrity of the air; it has only taught us that we are ignorant of
many things with which a few years ago we believed we were acquainted.
Daily experience appears in a certain degree to prove the fact that at
the Orinoco, Cassiquiare, Rio Caura, and wherever the air is very
unhealthy, the sting of the mosquito augments the disposition of the
organs to receive the impression of miasmata. When you are exposed day
and night, during whole months, to the torment of insects, the
continual irritation of the skin causes febrile commotions; and, from
the sympathy existing between the dermoid and the gastric systems,
injures the functions of the stomach. Digestion first becomes
difficult, the cutaneous inflammation excites profuse perspirations,
an unquenchable thirst succeeds, and, in persons of a feeble
constitution, increasing impatience is succeeded by depression of
mind, during which all the pathogenic causes act with increased
violence. It is neither the dangers of navigating in small boats, the
savage Indians, nor the serpents, crocodiles, or jaguars, that make
Spaniards dread a voyage on the Orinoco; it is, as they say with
simplicity, "el sudar y las moscas," (the perspiration and the flies).
We have reason to believe that mankind, as they change the surface of
the soil, will succeed in altering by degrees the constitution of the
atmosphere. The insects will diminish when the old trees of the forest
have disappeared; when, in those countries now desert, the rivers are
seen bordered with cottages, and the plains covered with pastures and
harvests.
Whoever has lived long in countries infested by mosquitos will be
convinced, as we were, that there exists no remedy for the torment of
these insects. The Indians, covered with anoto, bolar earth, or turtle
oil, are not protected from their attacks. It is doubtful whether the
painting even relieves: it certainly does not prevent the evil.
Europeans, recently arrived at the Orinoco, the Rio Magdalena, the
river Guayaquil, or Rio Chagres (I mention the four rivers where the
insects are most to be dreaded) at first obtain some relief by
covering their faces and hands, but they soon feel it difficult to
endure the heat, are weary of being condemned to complete inactivity,
and finish with leaving the face and hands uncovered. Persons who
would renounce all kind of occupation during the navigation of these
rivers, might bring some particular garment from Europe in the form of
a bag, under which they could remain covered, opening it only every
half-hour. This bag should be distended by whalebone hoops, for a
close mask and gloves would be perfectly insupportable. Sleeping on
the ground, on skins, or in hammocks, we could not make use of
mosquito-curtains (toldos) while on the Orinoco. The toldo is useful
only where it forms a tent so well closed around the bed that there is
not the smallest opening by which a gnat can pass. This is difficult
to accomplish; and often when you succeed (for instance, in going up
the Rio Magdalena, where you travel with some degree of convenience),
you are forced, in order to avoid being suffocated by the heat, to
come out from beneath your toldo, and walk about in the open air. A
feeble wind, smoke, and powerful smells, scarcely afford any relief in
places where the insects are very numerous and very voracious. It is
erroneously affirmed that these little animals fly from the peculiar
smell emitted by the crocodile. We were fear fully stung at Bataillez,
in the road from Carthagena to Honda, while we were dissecting a
crocodile eleven feet long, the smell of which infested all the
surrounding atmosphere. The Indians much commend the fumes of burnt
cow-dung. When the wind is very strong, and accompanied by rain, the
mosquitos disappear for some time: they sting most cruelly at the
approach of a storm, particularly when the electric explosions are not
followed by heavy showers.
Anything waved about the head and the hands contributes to chase away
the insects. "The more you stir yourself, the less you will be stung,"
say the missionaries. The zancudo makes a buzzing before it settles;
but, when it has assumed confidence, when it has once begun to fix its
sucker, and distend itself, you may touch its wings without its being
frightened. It remains the whole time with its two hind legs raised;
and, if left to suck to satiety, no swelling takes place, and no pain
is left behind. We often repeated this experiment on ourselves in the
valley of the Rio Magdalena. It may be asked whether the insect
deposits the stimulating liquid only at the moment of its flight, when
it is driven away, or whether it draws the liquid up again when left
to suck undisturbed. I incline to this latter opinion; for on quietly
presenting the back of my hand to the Culex cyanopterus, I observed
that the pain, though violent in the beginning, diminishes in
proportion as the insect continues to suck, and ceases altogether when
it voluntarily flies away. I also wounded my skin with a pin, and
rubbed the pricks with bruised mosquitos, and no swelling ensued. The
irritating liquid, in which chemists have not yet recognized any acid
properties, is contained, as in the ant and other hymenopterous
insects, in particular glands; and is probably too much diluted, and
consequently too much weakened, if the skin be rubbed with the whole
of the bruised insect.
I have thrown together at the close of this chapter all we learned
during the course of our travels on phenomena which naturalists have
hitherto singularly neglected, though they exercise a great influence
on the welfare of the inhabitants, the salubrity of the climate, and
the establishment of new colonies on the rivers of equinoctial
America. I might justly have incurred the charge of having treated
this subject too much in detail, were it not connected with general
physiological views. Our imagination is struck only by what is great;
but the lover of natural philosophy should reflect equally on little
things. We have just seen that winged insects, collected in society,
and concealing in their sucker a liquid that irritates the skin, are
capable of rendering vast countries almost uninhabitable. Other
insects equally small, the termites (comejen),* (* Literally, the
eaters or the devourers.) create obstacles to the progress of
civilization, in several hot and temperate parts of the equinoctial
zone, that are difficult to be surmounted. They devour paper,
pasteboard, and parchment with frightful rapidity, utterly destroying
records and libraries. Whole provinces of Spanish America do not
possess one written document that dates a hundred years back. What
improvement can the civilization of nations acquire if nothing link
the present with the past; if the depositories of human knowledge must
be repeatedly renewed; if the records of genius and reason cannot be
transmitted to posterity?
In proportion as you ascend the table-land of the Andes these evils
disappear. Man breathes a fresh and pure air. Insects no more disturb
the labours of the day or the slumbers of the night. Documents can be
collected in archives without our having to complain of the voracity
of the termites. Mosquitos are no longer feared at a height of two
hundred toises; and the termites, still very frequent at three hundred
toises of elevation,* (* There are some at Popayan (height 910 toises;
mean temperature 18.7 degrees), but they are species that gnaw wood
only.) become very rare at Mexico, Santa Fe de Bogota, and Quito. In
these great capitals, situated on the back of the Cordilleras, we find
libraries and archives, augmented from day to day by the enlightened
zeal of the inhabitants. These circumstances, combined with others,
insure a moral preponderance to the Alpine region over the lower
regions of the torrid zone. If we admit, agreeably to the ancient
traditions collected in both the old and new worlds, that at the time
of the catastrophe which preceded the renewal of our species, man
descended from the mountains into the plains, we may admit, with still
greater confidence, that these mountains, the cradle of so many
various nations, will for ever remain the centre of human civilization
in the torrid zone. From these fertile and temperate table-lands, from
these islets scattered in the aerial ocean, knowledge and the
blessings of social institutions will be spread over those vast
forests extending along the foot of the Andes, now inhabited only by
savage tribes whom the very wealth of nature has retained in indolence
and barbarism.