ON BRAZIL: ITS CLIMATE AND PEOPLE.
BY ROBERT DUNDAS, M.D.,
PHYSICIAN TO THE NORTHERN HOSPITAL, LIVERPOOL; FORMERLY SURGEON TO HER MAJESTY’S 60TH REGIMENT; AND FOR TWENTY-THREE YEARS MEDICAL SUPERINTENDENT OF THE BRITISH HOSPITAL, BAHIA.
Climate of Brazil.—Its salubrity.—Proofs of, causes of, objections to.—Northern, southern, and central provinces.—Equability of temperature.—Heat.—Humidity.—Rain.—Winds.—Electricity.—Hail.—Ice.—Tropical heat and light.—Influence on Europeans.—In health and in disease.—Acclimatization.—Increase of certain diseases.—Others modified.—Insanity.—Yellow fever.—Its probable disappearance.—Ancient writers on the epidemics of Brazil: Rocha Pita, Père Labat, Fereira da Rosa.—Physical, social, and moral condition of the Brazilians.—Habits and religion of the people.—Prophylactic measures.
In a publication like the present, any elaborate disquisition on the climate and people of Brazil would be obviously misplaced, at the same time that a brief notice of these important subjects should not be altogether omitted. The Brazilian empire placed chiefly in the southern hemisphere, extending from 4° 20″ N. lat. to 33° 55″ S., is widely intersected by lakes rivers and mountains, and bounded by the South Atlantic, by the highest mountains, and by the two most magnificent rivers in the world: it enjoys, beyond dispute, one of the finest climates of the globe, and may be fairly designated as ‘the Italy’ of the New World. The heat, intense at Pará on the equator, moderates as we approach the central provinces of the empire, and becomes altogether European on reaching the southern regions of Rio Grande and the Uruguay; whilst the climate of the entire line of coast is tempered by a cool and never-failing breeze. It should however be borne in mind that climate cannot be justly measured by latitude, and that we must, in all instances, take into consideration the position and the elevation of the district, the nature and surface of the soil, and its consequent capacity for the absorption and the radiation of heat. First, then, as regards heat, which may be termed the distinctive element of the climate of Brazil.
The mean heat of Brazil ranges from 88° to 81° F., according to the different seasons of the year.
Rio Grande do Sul.—The summer temperature is 87° to 88°; the winter, 40° to 44°.
Saint Catherine.—The summer heat never passes 90° in the sun; and descends to 54° in winter—June and July.
Saint Paul.—Mean temperature, 72°.
Minas Geraes.—Max., 84° summer; min., 54° winter.
Rio Janeiro.—The mean temperature of 30 years was 73°: in December, the max., 89½°; min., 70°; mean, 79°; in July (coldest month), max., 79°; min., 66°; mean, 73½°.
Bahia.—Summer: 74° morning; noon, 80°; evening, 75½°.
Pernambuco.—Summer: Varies from 77° to 86°, with a slight decline in the rainy season.
Ceara.—95° in the hottest months; 83° in the coldest.
Maranham.—St. Louis reaches 93°; and Pará, on the line, maintains about the same temperature.
The hottest period of the day, on the sea coast, is about 11 a.m., when the sea-breeze commonly sets in and moderates the temperature. The thermometer ranges in the northern provinces on the coast, at midday, 75° to 77° from March to September, and 77° to 85° from September to March; whilst at forty to fifty miles inland a high range of temperature almost invariably prevails. The barometrical variations are less extensive than those of the thermometer; but the range of the hygrometer is considerable in the southern provinces. The object, however, of the present work prohibits our entering minutely on these questions, or on the geology of Brazil; and we must therefore refer our readers to the scientific labours of M.M. Eschwège, Sellow, Spix and Martius, and Saint Hilaire, and especially to the valuable and more recent investigations of M. Pissis, who has explored the country from 13° to 26° south latitude, and 40° to 52° west longitude, including in this vast polygon the provinces of Minas Geraes, St. Paul, Rio de Janeiro, Espirito Santo, and Bahia.[72] The observations of Herschel, Humboldt and others, prove that both heat and cold, up to 34th degree of latitude, are much more moderate in the southern than in the northern hemisphere; in addition to which, Brazil, covered by extensive forests and consequent moisture, the surface clothed with perpetual verdure, from which the solar heat is but feebly reflected, its skies ever bright and a never-failing breeze, constitute a climate of unequalled mildness in any other region of the tropical world.
Humidity: This grand and universal source of vegetable life in high latitudes is infinitely more detrimental to man than even the highest solar heat. Humidity, indeed, is the great modifier of all climates, and constitutes the chief element of their insalubrity. The hygrometrical variations of Brazil have been studied by numerous observers, amongst whom the most accurate as well as the most recent is M. Pissis, and to his conclusions we shall briefly allude, confining ourselves to the climate of the capital, Rio de Janeiro, which, notwithstanding its clear atmosphere, holds in solution just double the quantity of aqueous vapour sustained by the sombre, foggy air of Paris! a fact explained however by the high temperature of the one, as compared with the low temperature of the other, the capacity of air for retaining moisture being in nearly exact proportion to its temperature. M. Pissis arrives at the following results:—
1. From May to October, when the air is serene, the quantity of vapour varies little throughout the day. During the other months, the minimum corresponds with sunrise, and attains its maximum about 4 p.m.; but the variations are trifling.
2. That on rainy days the air is always near its point of saturation, though the amount of vapour dissolved little exceeds that of the preceding clear weather: this is due to the lower temperature of the rainy days.
3. That humidity increases from the month of June to February, when it attains its maximum, which is about double that of June; from this maximum it declines until it reaches its former amount in June and July.
4. That the absorbing power of the air is lowest at sunrise, and attains its maximum about 2 p.m., the hottest period of the day. In like manner as regards the year, it augments in proportion as the sun advances to the southern tropic, and attains its maximum in December and January, and then declines until the cloudy months of June and July.
Rain: The wet season sets in at different epochs along the coast of Brazil, and is subject to great variation. At Rio the rains commonly commence in March, and last till September; at St. Paul, in October and November, and continue till April; whilst at St. Catherine the four seasons are, as in Europe, pretty distinctly defined—July and the following three months wet, cloudy, and boisterous. These latter provinces, placed just beyond the Tropic of Capricorn, enjoy the advantages of a tropical climate without its inconveniences. Rio Grande do Sul is wet and stormy in the winter months, but otherwise healthy. In the provinces north of Rio, including Bahia and Pernambuco, the rains set in commonly about the end of March, and continue until August; and as we follow the coast to the equator, including the provinces of Ceara, Maranham, and Pará, storms are frequent, and the rains commence in December or January; August, September, October, and November being the dryest or summer months. The foregoing may be taken as the rule, but the exceptions are numerous; and the winter of the coast does not extend beyond 100 miles into the interior, which is watered, chiefly, by frequent storms.
Winds: The general winds of tropical regions are eastern; and in Brazil the prevailing currents along the coast, from St. Catherine to Maranham, are E.S.E., and S.S.E., during the southern, and E.N.E. and N.N.E. during the northern monsoon; subject however to much irregularity. The land breeze sets in from 9 to 11 p.m., and lasts till morning, increasing in force and regularity as we approach the equator; and its strength is generally in proportion to that of the sea breeze which precedes it. As in other tropical countries, the sea breeze prevails more in the hot, and the land breeze in the cold season of the year; they favour the appearance of certain maladies and check others, and constitute, after heat and moisture the chief element in the determination of disease—the salubrity of any country depending more, perhaps, on its winds than on its latitude.
Electricity: All tropical regions are distinguished by intensity of electrical phenomena, and Brazil forms no exception to the law. Réaumur maintains, and we believe justly, that a difference of 5° in the thermometer decidedly affects the nervous system; and that all living organisms are powerfully influenced by electrical changes no close observer in equatorial regions can for an instant question. In Brazil, the most intense variations are noticed about the change of the monsoons, and the storms of lightning and thunder originating in the great chain of the Organ Mountains, which burst over Rio, are grand and awful beyond the possibility of description; whilst the profound influence of these changes on individuals is strongly pourtrayed in the moral and physical prostration of some, and the high nervous excitement of others. Saussure has shown that an excess of watery saturation diminishes atmospheric pressure; and the effect of certain conditions of the atmosphere on the human economy in tropical climates cannot for a moment be denied: for example, when the weather is wet and cloudy, the sun obscured, and the air calm; all animal life languishes. The Brazilians distinguish this state of atmosphere by a particular term, ‘mormaço,’ and during its continuance, especially in summer, the mental and bodily powers of man seem alike paralysed, and are only restored to activity when the rain has descended and the breeze resumed its power over the close and stagnant atmosphere. Here electricity plays an important part. In connection with this subject, it is remarkable that Brazil should have hitherto escaped those formidable earthquakes which have so often desolated the fairest regions of South America. Fogs are rare in Brazil, and seen only in the morning, on low and marshy grounds, and in the neighbourhood of rivers and lakes. Hail often falls in Minas, St. Paul, and the south, and even occasionally at Rio. Ice is sometimes met with at Rio Grande in the winter, and even on the Organ Mountains, close to Rio, but never snow. Waterspouts have been, at long intervals, observed on the coast and in the interior; the last of any importance was observed at San Marcos in 1823.
Based on the foregoing and other data, we shall now submit certain general conclusions on the climate of Brazil, and its influence on the human constitution in health and disease; these conclusions must be taken as more especially referring to the seaboard and the large cities on the coast; and the reader should bear in mind that some allowance must also be made for the difference in position and latitude of the northern, the southern, and the central provinces. We would further premise, that these observations are founded on our own personal experience of nearly a quarter of a century, and prior to the advent of the yellow fever which, for the last four or five years, has infested the maritime cities of the empire, and on which we shall presently offer some remarks.
The great characteristic of Brazil, as compared with other countries, is the general equability of its climate, and which constitutes, in fact, the chief element of its salubrity. This unparalleled uniformity of temperature must be chiefly ascribed to the absence of high and mountainous regions, and of all arid and sandy deserts, aided by the genial influence of refreshing showers at all seasons of the year; it is further maintained by the perpetual verdure of the country, and by a cool, powerful, and never-failing monsoon, laden with moisture, and sweeping along the entire line of coast direct from the Southern Atlantic. Thus, even in the height of summer, the diurnal heat is rarely found oppressive to the European, and the nights are almost invariably serene and beautiful, and unattended with much deposition of dew, especially in the northern and central provinces; so that the delightful coolness of tropical moonlight may be enjoyed undisturbed by those visions of fever and malaria which float before the imagination in less favoured lands. If precautions be observed to avoid exposure to direct currents of air, the windows of the sleeping chamber may also be left open with impunity at all seasons of the year; an advantage that can scarcely be over estimated in high latitudes, as disposing to sound and refreshing sleep; which, more perhaps than any other influence enables the European constitution to resist the deleterious effects of climate, just as a succession of hot and sleepless nights invariably predisposes the human system to be impressed by every tropical malady.
In proof of the singular salubrity of Brazil, we need only state that, until within the last four years, although its provinces have been at intervals visited by revolutions, wars, and famine, the country has hitherto escaped from all those epidemic and endemic scourges—yellow fever, cholera, influenza, typhus, and dysentery—which have so frequently desolated other, and the fairest regions of the globe. In this favoured land the solar heat proves scarcely less influential and salutary to animal than to vegetable life; and years of subsequent exhaustion can never entirely efface from the recollection of the European sojourner the buoyancy of spirit, unclouded mind, and exquisite appreciation of mere animal existence which marked the first years of his residence in Brazil. These vivid sensations may be in part determined by the novelty and splendour of a New World, its brilliant skies, perpetual verdure, and the variety, luxuriance, and beauty of its vegetable life; but they are chiefly due to the direct influence of the heat and light of a tropical sun, supplying a new and powerful stimulus to the performance of all the functions of animal and organic life. The medal, unfortunately, has its reverse: this favourable condition of the animal economy proves, as in vegetable life under similar circumstances, but of limited duration; and from five to seven years may be set down as the average period at which a tropical residence begins to affect the European constitution to such an extent as to influence longevity or injure health; the precise epoch being determined by the constitution, occupation, predisposition, and habits of the individual. It should be here stated that the month of April is that best suited to the stranger’s arrival in Brazil, as affording time for his gradual acclimatisation to the summer heat of December, January, and February; though we may observe, and the fact is singular, that the European suffers but little inconvenience from the highest temperature during the first years of his residence, just as the Brazilian seldom complains of the winter cold on his first arrival in Europe. The chief objection to the climate is, in addition to high temperature, its great humidity; shown in the rapid decomposition of all organized, and certain inorganic matter, the quick oxidation of metals, deliquescence of salts, destruction of wood, &c. &c.; and after a certain interval, the depression of moral and physical energy in man. The deleterious effects of this condition of atmosphere on the animal economy is happily tempered, if not entirely corrected in Brazil, by the general equability of its climate, and the influence of a cool and never-failing breeze, so that a stagnant, or even calm, state of the atmosphere is almost entirely unknown. Were this otherwise, the chief cities of Brazil inundated by the most offensive animal and vegetable exhalations,[73] and with an almost total neglect of those policial and sanatory regulations so essential to the public health in other countries, would, we are satisfied, prove no less fatal to man than the charnel houses of Africa and the West Indies.
In estimating, however, the influence of climate on the public health, the moral and physical condition of the people demands especial consideration. The Brazilian is in general well-formed, compact, and of healthy organization, but not of athletic frame. His intellectual faculties are acute, though little developed by cultivation. Descended from European ancestors, he has still a considerable admixture of African, and some native American blood. He is indolent by nature, and indisposed for active exertion or industry; but he is protected against the evil influence of the former on his health by a simple and abstemious diet, and the injurious consequences of the latter to his social position are obviated by the fact that the four great wants of the humbler classes in Europe press but lightly on the Brazilian. Fuel he scarcely requires, clothing but little; his primitive habitation is simply constructed, and one day’s labour will amply provide for the moderate demands of the whole week. With passions naturally quick, he is nevertheless placable; his disposition is kindly; the future rarely disturbs him with its doubts, or the past with its regrets: the struggles and vicissitudes of European life are unknown. The contentions of party, the yearnings of ambition, the bitterness of fanaticism, never disturb his repose; and after gliding down the stream of time, unscathed by the tumultuous passions and harassing cares which so frequently embitter the existence and undermine the constitution of man in other countries, he meets at length the inevitable doom, if not with philosophy, at least with resignation, satisfied of his claims to eternal felicity in the confident assurance of an infallible church.
From the preceding account of Brazil and its inhabitants, we would be led to conclude, à priori, that disease would there assume a mild and tractable character; and this inference we find fully borne out, until within the last twenty years, by the medical and general history of the country. Within the last thirty years, however, vast changes—moral, social, and political—have been developed in Brazil, and it interests alike the philosopher and the physician to mark how profoundly these changes have already impressed and modified the manners, habits, and diseases—nay, even the physiognomy of its people. After a brief struggle, the establishment of Brazil as an independent empire was effected in 1823; and since that epoch the country and its population have undergone a series of remarkable and comprehensive political and social changes. From the strict and simple forms of despotic government they have passed, at a bound, to one almost of license; including household suffrage, popular legislative assemblies (imperial and provincial), open courts of law, trial by jury, local justices, and a national guard elected on popular principles. This sudden and premature concession of political privileges to a people yet in the infancy of civilization has been naturally attended by great and numerous evils, mingled, it must be admitted, with many and great advantages. In the intoxication of a new-born freedom, the empire has committed numerous excesses; province has been arrayed against province, in a succession of intestine broils; the laws have been inefficiently or corruptly administered; and a lax morality has but too generally pervaded the whole community. On the other hand, an extensive and well-organized system of national education has been established throughout the empire; the slumbering intellectual powers of the nation have been aroused; wealth and intelligence developed; political and military ambition awakened; commercial enterprise created; agriculture revived; and of all those mighty powers which move and mould societies, the controlling influence of religion has alone remained stationary. The priesthood, deprived of wealth, power, and influence, has utterly-lost its prestige, unless, perhaps, with the very lowest classes of the community—a question of curious speculation as regards the cause, and of vast importance as regards its future results on the character and institutions of the Brazilian people. In addition to the foregoing rapid transition of society into new forms and combinations of social existence, we find the face of the country changed by the march of civilization and agricultural improvement,—woods cleared, roads opened, internal and external navigation developed, population largely increased, and the great maritime cities of the empire assuming an importance second to none, and superior to most, of the cities of the new world.
Coeval with these great and rapidly advancing changes, we can already discern some of those evils too commonly attendant on increased wealth, luxury, and intelligence: anxieties, excesses, passions are largely multiplied, and the medical observer cannot fail to distinguish, amongst certain ranks of the hitherto contented and indolent Brazilians, unequivocal traces of that premature ‘wear and tear,’ so strongly and painfully characteristic of high civilization. It now only remains that we should briefly notice the extent to which certain great classes of disease have been influenced and modified by the preceding moral and physical agencies. This is chiefly manifested in the increasing number of cerebral and pulmonary maladies, and diseases of the heart and great vessels. Insanity has also become much more frequent than formerly, though still rare as compared with other nations; which, indeed, might be inferred from the fact that the ‘Mad Doctor’ is a species of the profession as yet unknown to Brazil. Suppurative inflammation of the liver has increased, but of all the acute diseases, fevers have been the most profoundly modified; they partake much more generally of the low, or asthenic character, and assume the remittent and continued type, and are greatly more fatal in their results than formerly. This naturally brings us to the important question of the ‘yellow fever,’ which for the last four or five years has ravaged the great maritime cities of the empire. Its origin has given rise to the most conflicting views, amongst the best observers;—for example, Dr. Pennell of Rio, and Dr. Paterson of Bahia, both men of undoubted talent and great professional experience, entertain precisely opposite opinions; the former contending for the indigenous, the latter for the foreign origin of the disease; and both offer cogent arguments and striking facts in support of these opposite conclusions. The scope of this work does not admit of medical discussion, yet as the facts observed by Dr. Pennell are highly important, and as his conclusions entirely coincide with our own experience, we will condense them here. Dr. Pennell states that for some years the fevers of the country had been clearly changing their character, that the genuine remittent had been little seen for three years; that it was replaced in 1847, ’48, and ’49, by a fever of its own class, popularly known as the ‘polka fever,’ but in reality a remittent; and that this fever was, in its turn, superseded by the ‘yellow fever,’ a disease with similar features: he adds the following words, ‘coincident with these and other changes in the diseases of Brazil, the climate, in its broad features, has altered strangely: thunder-storms, formerly of daily occurrence, at a certain hour, during the summer, are now but seldom heard, &c.,’ and concludes, ‘that bilious remittent and yellow fever are essentially the same disease,’—a proposition entirely in accordance with my own experience in Brazil and other countries. The abettors of the foreign origin of yellow fever insist that it was imported by a certain ship from New Orleans into Bahia, and thence diffused throughout the empire; whilst the facts adduced by Dr. Pennell go far to establish, as already stated, its indigenous parentage. In support of this opinion we have the strong additional fact that, for the last forty years, there has existed uncontrolled by any efficient quarantine laws, an extensive intercourse with the United States, Africa, and the West Indies, the very hot-beds of yellow fever; and yet, up to 1849, Brazil remained perfectly healthy. Can we then in reason believe, if the disease be deemed really importable, that the maritime cities of Brazil could, under such circumstances, have escaped infection for a period of forty years? It is moreover important to know that several of the older writers, as Rocha Pita in 1666, Père Labat in 1686, Fereira da Rosa in 1694, have recorded the appearance of epidemics closely resembling the yellow fever, and which, after persisting for some years and desolating several of the large cities on the coast, finally passed away. Some seventy years ago, the capital itself was visited by an epidemic fever no less fatal to the population than that from which it now suffers.
From the above and other facts, we are firmly convinced that the yellow fever which now afflicts Brazil is not an imported disease, but owes its origin to certain obscure atmospheric disturbances, embracing variations of temperature, hygrometric influence, electrical tension, atmospheric pressure, &c.; and judging from the previous history of Brazil, we believe that these unfavourable conditions are but temporary and will pass away, and that the country will again resume its former character of unparalleled salubrity amongst the tropical regions of the globe.[74]
Prophylactic Measures.—A few words on the precautions to be adopted by temporary as well as permanent residents in Brazil may perhaps prove useful. In the first place, all the ordinary hygienic laws should be attended to; the habitation selected should be in a dry locality, on a moderate elevation, and well ventilated, but at the same time protected against strong currents of wind; lengthened or direct exposure to the sun’s rays should be avoided, and all sudden vicissitudes of temperature guarded against. Loose waistcoats without sleeves, of fine flannel, should be worn next the skin, during the day, but never slept in; sleeping in the open air or unprotected, should be avoided. After exposure to rain, the clothes should be immediately changed; after exhaustion by exercise, or from any other cause, collapse or chill must be carefully guarded against, by avoiding for a time exposure to the cool breeze or by taking some slight stimulant, as coffee, wine, or a little spirits. Spirits, otherwise, should be altogether avoided, and wine resorted to only at dinner, in great moderation, and by those accustomed to its use. Generally, animal food should be used only at dinner; no supper; and no stimulating drinks, however diluted, should be taken between meals. Ripe fruit may be used before breakfast, and after the middle of the day, but never after the principal meal. Moderation IN EVERY SENSE must be observed. When compelled to go out early in the morning, the individual should take some support. In warm and swampy districts, over fatigue, or prolonged exposure to the sun, cannot be too carefully avoided, and the use of quinine, in moderate doses, should never be neglected; the cold bath, or cold sponging, every morning on getting out of bed, should be constantly resorted to. The sleeping apartments should be cool and well ventilated, but not exposed to strong currents of air.
Of all the above principles, refreshing sleep is the most efficient preservative to the European constitution against the inroads of tropical disease; but unless the above rules are pretty closely observed, sound and refreshing sleep in equatorial latitudes is unattainable. The morale must never be lost sight of, and a calm and cheerful disposition of mind should be especially encouraged. The above prophylactic measures apply with equal or greater force to the European seaman on arrival in Brazil. In addition, awnings by day and by night are absolutely indispensable to health. Fatigue and dockyard duties, and watering expeditions, should never be permitted during the mid-day heat, nor should the seaman ever be permitted to sleep out of his vessel. The high importance of this latter injunction will be obvious from the fact that a difference of fifty degrees will be found often to obtain between the heat of a mid-day tropical sun and the air near the earth’s surface at sun-rise. Surely, then, we need not evoke the phantom Malaria to account for the sudden supervention of malignant or fatal disease in seamen, or others, exposed during sleep to such great and sudden transitions of temperature, especially when their animal and organic powers have been depressed by previous exertion and profuse perspiration under a tropical sun, aided, too often, by intemperance and other excesses.
Nec Deus intersit nisi dignus vindice nodus.
Finally, we are profoundly convinced, by long and large observation, that if the foregoing principles are attended to, the most formidable localities of southern climates may be encountered with impunity, and especially as regards that dreaded, but visionary enemy, Malaria or marsh poison.[75]