INTRODUCTION.

AComparative View,&c.INTRODUCTION.A Sketch of our Planet’s Station, Rotation, and Rank amongst the other Celestial Orbs; and of its Investing Elements:—of the Habitable Parts of our Planet: the Number of the Human Species, and their Division into various Classes, Genera, Groups, and Gradations: their Comparative Births.Thereare two methods of promoting Medical Knowledge: one by negative information, or criticisms on the numerous errors of preceding authors: the other by direct instruction, and improvement on former models. The first method is wornout in hackneyed chimes: the second is encumbered with infinitely more difficulties; and its merits paramount in the superlative degree. However unequal I have imposed upon myself the latter task. But, previous to the discussion of the general theme, it will conduce to order, and to the anticipation of explanatory digression and illustration, to glance at the station, rotation, and rank of our Parent Planet amongst the other celestial orbs; at its investing elements; and at the number, groups, and recruit of mankind. A navigator or historian, who undertakes the description of any island, kingdom, or continent, commences with their geographical outlines and climate, penetrating afterwards thorough a scrutiny of the inhabitants. Upon a similar, but more majestic model, our Introductory Preface is founded. Throughout the whole of this intricate, sublime, and inexhaustible subject, if I do not delay sufficient time to fix, I shall at least hope to start the reader’s attention to a variety of grand objects, inseparable from a comprehensive knowledge of Medicine; and of which I shall touch the fundamental keys and chords.The Solar Systemconsists of the Sun, of seven Planets surrounded by ten or more Moons, and of the Comets. The other siderial lights with which the vault of Heaven is studded, and which are denominated Fixed Stars, have a very distant affinity with our planetary sphere: they are infinitely too remote to be enlightened by our luminary; and therefore astronomers, with good reason, imagine each star to be a sun to encircling planets, though invisible to us; and to constitute throughout boundless space thousands, or perhaps millions, of habitable worlds. Numbers of those stars, most luminous and proximate, are arranged into arbitrary clusters, called Constellations, or Signs; and serve to mark the several stages of the rotating orbs in our system.The Sun, whose magnitude far surpasses that of the seven planets united, is placed in the center, suspended in the immense celestial expansion and firmament. Surrounding him, at different distances, and in the following order, are the planets Mercury, Venus, the Earth, Mars, Jupiter, Saturn, Georgium Sidus. These planets are incessantly revolving from west-by-south to east, and within certain intervals of time, make a complete circle round the Sun; which is the length of each planet’s year; and is larger and longer in proportion to their respective distances. The velocity of their revolution in their annual orbits, together with their gradations of light and heat, are also in proportion to their solar proximity. From the Sun, the Planets, with their surrounding moons, derive heat and light; and when this is intercepted by any planet, or its satellite, an eclipse or darkness ensues. In what periods those tremendous celestial bodies, named Comets, revolve round the Sun, is not yet exactly adjusted.One of the seven planets, the Earth, this small domain of restless mortals, and to which all our future observations shall be directed, is distant from the Sun 95,173,000 miles. In shape, it has more resemblance to a turnip than to a globe. Its diameter is 7,970 miles: its circumference 360 degrees; which amounts to 24,840 English miles. Geographers divide the globe of ourplanet into two equal parts, or hemispheres, the northern and southern, by an imaginary girdle, or ring, named the Equator. Two other imaginary girdles surrounding the earth, and distant from the equator on each side 23½ degrees, north and south latitude, are named the Tropicks of Cancer and Capricorn; comprehending between them the torrid zone. From these tropical circles the zones, called Temperate, extend on each side 43 degrees: and at their extreme boundaries, we reach the polar circles 23½ degrees distant from each pole. The north and the south poles are in the middle of each hemisphere of the earth; and the distance of each from the equator is 90 degrees.The earth has several incessant motions: one in which it turns, like a suspended wheel upon its own axis, from west to east, every twenty-four hours, which is the length of its day and night: the second, where it is rolling progressively in its great annual circle, or journey round the Sun: the third, the alternate inclination of itspoles towards the sun at different times of the year: the fourth, the small circle which it describes monthly round the common center of gravity, or balance, with its moon. The earth’s diurnal revolution upon its axis, is at the rate of fifteen degrees, or 1,035 miles hourly. But the rapidity with which it is whirled in its annual orbit, is, hourly, 68,243 miles: whereas the swiftness of a ball discharged from a cannon is, in the same time, only 480 miles. Projected through the vacuity of heaven with this amazing velocity, in the space of 365 days, 5 hours, and 49 minutes, the earth completes its annual circle; which is the length of our year. The earth’s rotation every twenty-four hours upon its axis, is the cause of day and night, or of light and darkness. In this successive rotation, one half of its globular surface is always enlightened; the other half being then obscured in nocturnal gloom, except when enlivened by the reflected rays of the moon, or of one of the planets, or by the fainter glimmering of the fixed stars. The alternate spiral inflection and declination ofthe earth’s poles during its annual journey round the Sun, is the cause of the different lengths of Days and Nights; of the Seasons; of Summer and Winter; of the Equinoxes, and Solstices: and as each pole inclines or recedes, it is summer and winter, alternately, in their respective hemispheres. The effects of this compound terrestrial circumvolution on the animal and vegetable creation, would alone be a magnificent theme for many volumes.One Moon only is allotted to our earth; from which it is distant 240,000 miles. The moon’s diameter is nearly one fourth less than that of the earth, which it obsequiously accompanies throughout its annual circuit; and round which it makes a perpetual revolution, from west to east, every lunar month. The constant agitation and periodical surges of the ocean, are greatly influenced by the moon, assisted, however, by the centrifugal force of the earth’s motion. It is also ascertained, that in some diseases, the human body is considerably under the lunar influence; and its energy is still more conspicuousat periodical changes, during the month and the year. Many arguments might be suggested to invalidate and overturn the ancient astrological systems, and to prove that the celestial influences upon us are not, in any considerable degree, derived from sources more remote than the solar confines.The first Element in pre-eminence and subtility, without which all would be lifeless chaos in our system, is Heat and Light. Cold is a negative quality, and merely a comparative diminution of heat. The middle regions of the earth being repeatedly more exposed to the Sun’s vertical rays, are consequently most heated and scorched. From the equator to the poles, are all the gradations of heat and cold; but for reasons too prolix to enumerate, these gradations are not in exact measurement with the geographical distances from the equator; neither in the same continent, nor in different continents. By the scale of Farenheit’s thermometer, water boils at 212, freezes at 32; and blood-heat, or that of the human body,is about 97. The most intense heat of the tropical regions, as measured by the same thermometer, is frequently many degrees above the human temperature; and the most intense cold of the polar regions, often many degrees below 1 or 0 of the same scale. Neither of these noxious extremes of pestilential heat, nor of deadning blasts from boreal snow, could be long endured by the human species, were their bodies not protected and skreened by fences of nature or of art. Atmospheric heat, equal even to that of the human body, is felt intolerably scorching and suffocating. Every one also knows, by personal experience, that in different latitudes, and in summer and winter, the degrees of heat and cold, the duration, recurrence, and changes, are extremely variable. But within the equatorial limits, these variations are much less conspicuous, both in the thermometer and barometer. From this main spring and soul of animated nature, blessings and bounties are diffused, in thousands of channels, to every order of the creation; and from its extremes and vicissitudes, a multitude of evils and diseases are inflicted upon man.Between the earth and celestial vacuum is interposed an element, called the Atmosphere, or Air. This invisible elastic fluid is floating equally round our planet, to the distance of at least forty-five miles perpendicular elevation. It has been compared by some philosophers, to packs of wool heaped on each other: that nearest the ground is most dense, compact, and ponderous; and as we ascend, it becomes gradually more rare, light, and cold. The prodigious gravity, or pressure, of this atmospherick column, appears incredible to those who are ignorant of experimental philosophy, and of the air-pump and barometer. Upon a man’s body, of middle stature, its weight is equal to thirty-two or thirty-three thousand pounds: but in rainy and variable weather, and especially on the summit of high mountains, there is a diminution in its pressure of many thousand pounds. This great mass of air, as well as the waters of the ocean and of rivers, is in constant agitation; sometimes gliding in gentle calms; sometimes, with wild uproar, raging in storms and hurricanes, and dispersedin a variety of currents, over different parts of the earth and ocean in Winds, constant, periodical, variable, and irregular. Without the concurrent support of air, animal and vegetable life would soon be annihilated. On them great and sensible effects are produced by the atmosphere and winds: by the air’s noxious impregnation, stagnation, want of elasticity, heat, cold, moisture, dryness; by the points from whence winds blow, their constancy, irregularity, recurrence, velocity.The earth is the cistern, and one principal fountain of another still grosser element. From the Sun’s heat, and from the successive streams of air and winds, a prodigious evaporation is carried on from the surface of the ocean, from the land, and from vegetables. Whether part of the atmospherick air is also converted into vapour, is a question too intricate and diffuse for our present inquiry. The critical analysis and history of a single element, would alone far exceed the limits of this Dissertation. It is sufficient for us to observe, that these vapours, terrestrial and aerial, are collected intoclouds, condensed, and again discharged upon the earth in Dews, Mists, Fogs, Rains, Snow, and Hail. The precipitation likewise of this accumulated vapour upon different parts of the globe, is periodical, regular, and variable. In quantity, duration, recurrence, and extent, these aqueous modifications are greatly diversified by the climate and soil, the vicinity to mountains and sea-coasts; the points from whence winds blow; and by many other causes, of which a detail cannot be here expected. From this source also ensue salutary and baneful effects, innumerable to animal and vegetable life.Another subtile and active agent in the secret machinery of nature, is the Electrical Emanation; which, somewhat perhaps analogous to the aqueous evaporation and congestion before mentioned, is collected into clouds, and, with loud explosion, again discharged and dispersed into the air and earth: the fabulous thunderbolts and artillery of Omnipotence.We now alight upon that solid mass, Earth, the most fixed and substantial of allthe elements. The surface of our planet is composed of dry land and water; of which the ocean, without including lakes and rivers, occupies by much the largest extent. But the partition of the dry land into four continents, Europe, Asia, Africa, and America, is not well founded. Nature has in reality formed only three great insulated continents, exclusive of the smaller islands. Europe and Asia are contiguous, and cemented together as England and Scotland; or as France and Germany; and their boundaries artificial: whereas Africa, except the slender neck of land near Alexandria, is surrounded by sea. Of these four continents, Europe is the most diminutive. Asia and America stand dignified, above all the others, in superior magnitude. The dry land in Europe, Asia, and America, stretches to a great northern latitude, considerably within the arctick, or polar circles; and, spreading also in that part to a wide extent, east and west, forms nearly a complete bridge between Asia and America. Within the tropical circles are included the belly and bulge of Africa, and of SouthAmerica, with a considerable portion of the broken southern extremities of Asia; together with most of the principal islands in the Pacific and Atlantic oceans. In all the hemisphere south of Capricorn, the land is greatly disproportioned to the ocean. The conical south point of America is but 55, and that of Africa only 35 degrees distant from the equator. A vast orbicular segment of this extreme of our planet, furnishes habitation for fishes only. The dry land is also diversified by elevations and plains; but in no part of the earth’s circumference do those stately monuments of nature’s workmanship ascend to five miles perpendicular elevation.The Creator has bountifully stored the earth and the ocean with animals and vegetables. Our attention is here circumscribed to the most exalted class, the Human Species; leaving to the naturalist a description of quadrupeds, birds, fishes, insects, and vegetables. By far the largest proportion of the human species are stationed to the north side of the equator, and even to the north of the tropick of cancer. The populous continentsof Europe and Asia, comprehending most of the powerful kingdoms in our planet, are in the northern hemisphere. Within the tropical circles and furnace of the earth, are stationed the next considerable hive of mankind. To the south of Capricorn there are few inhabitants. Some wretched human beings are also scattered through those dreary wastes of ice and snow within the northern polar circles.Calculators differ enormously respecting thenumber of the Human Species. Some sink the collected herd so low as three hundred million, whilst others exaggerate them to treble and quadruple that amount. It forms no part of my scheme to investigate the comparative population of the earth, one, two, and three thousand years ago. Europe, in all probability, since the era of Roman grandeur, has, together with advancement in civilization, likewise added to the number of its inhabitants. Those parental nurseries of the arts and sciences in Asia and Africa, have no doubt undergone various revolutions in population. If we were to draw any inferences from the numerousAsiatic armies, during the successive despotism of Assyrian, Babylonian, Medean, and Persian monarchies, we should conclude that, in remote ages, the south of Asia abounded in men. The extensive empire of China, at this day, resembles an industrious beehive, and is gorged with mankind. We have still more aversion to plunge into the mysterious archives of Africa, and with critical affectation to pronounce upon the population of that quarter before the decay of its political, commercial, and literary fame with Thebes, Carthage, and Alexandria. That modern-discovered transatlantic continent, from the cruelties and desolation of its first conquerors, and of a loathsome infectious disease exchanged for another, has probably suffered considerable diminution of its original feeble hive, notwithstanding the recruit from Europe; and in the scale of population, as yet ascends to a very subordinate rank amongst the other continents. The most probable calculations estimate the whole human race at eight hundred million: of which number, Europe boasts of little more than one hundred million. The great swarm is in Asia; amounting tobetween four and five hundred million. Africa is supposed to contain one third or fourth of the latter number. Over the fertile wilderness of America are scattered not altogether twenty million.But if in London alone, where registers of various kinds may be consulted, calculators are, notwithstanding, at variance respecting its population upwards of one hundred thousand, and in the whole island more than a million; it may be reasonably suspected, that in forming a gross estimate of the aggregate terrestrial inhabitants, we may err perhaps, one, two, or even three hundred million. As well might we expect a correct list of the lions, crocodiles, and monkies of Africa, as of the outcast human race in those burning and illiterate regions. To determine the exact amount of inhabitants in any civilized kingdom, the most certain method would be, to make an universal and arithmetical numeration throughout every dwelling. This is often done in several kingdoms; and in none more culpably neglected than in this island. English calculators, therefore, have been under thenecessity, by other laborious processes, to form at least plausible conjectures of the national population. One of their methods is, by collecting the number of houses, and allotting five, or four and a half inhabitants to each house; which, at a general medium, was found near the standard of truth, in a multitude of large towns and open districts in England, Holland, Germany, Switzerland, and Italy; as may be seen recorded in the writings of Short, Susmilch, Price, and many others. In some particular cities, however, such as Berlin, Vienna, Paris, and Edinburgh, where several families are crowded into one house, this rule would lead into error. Besides, in ours, and many other large kingdoms, we are not yet supplied with an authentick register of all the dwellings. And in Asia and Africa, whose political institutions and customs are so different from us, this scale of mensuration may be still more erroneous. Another method, but still more complex and uncertain, of computing the population is, by the annual christenings and burials. When these are equal, and consequently there is no increase or decreaseof the inhabitants, we are directed to multiply the usual prospect or decrement of life, or in the mathematical phrase, the expectation of an infant at birth in that city, town, or district, by the general medium of christenings; which will be the total local amount of the inhabitants. But as the christenings and burials are rarely equal, or a correct list of either can be ascertained from the imperfect registers, this process is very defective.The Multiplication of the human species depends greatly on society. There are more inhabitants concentrated into one large metropolis of Asia or Europe, than could be collected in many thousand miles of the North-American wilderness on its first discovery. The population of the earth is by no means regulated by the extent of country. If, on the one hand, high refinement and large cities are obstacles to population, a wild state of nature is still more detrimental. A few tribes of North American natives, prowling like hungry wolves, can scarce find precarious subsistence in a wide extent of uncultivateddesarts. Their infants, from necessity, are suckled several years; and after rearing two or three, the period of propagation is nearly over. A medium state between the vicious extremes of refinement and rude savageness; or the middle stages between the iron and golden ages of the ancient philosophers, is most favourable to the increase of our species. But the causes conducive to population and depopulation, are of infinite compass; and are of a compound nature, medical and political. They are connected with the state of government, religion, climate, genius, industry, riches, poverty, taxes, luxury, refinement, wars, colonization, emigration, commerce, agriculture, the unequal distribution and monopoly of property and farms, the plenty, scarcity, and cheapness of food; and, with many other causes, closely allied to our future medicinal investigation. Under governments and nurture, directed with political and moral, together with medical prudence and circumspection, the earth and ocean would probably afford ample nutriment, and their population might be multiplied to three times eight hundred million.Extending our views over the surface of the globe, we perceive striking distinctions between the human species; not only in the four great continents, but also in different parts of the same continent. These differences are principally manifest in the colour of the skin; in the complexion, countenance, physiognomy, hair, form, and stature. We attend here merely to corporeal distinction, without including the intellectual. These great Classes of mankind may be divided into the Laplander, the Tartar, the Chinese, the European, the African-negro, and the native American. The modern-discovered inhabitants in the islands of the Pacific ocean, seem to have no remarkable cast of countenance or figure to sever them into a separate class. But throughout a considerable extent of the globe, from conquest, emigration, colonization, and commercial intercourse, many nations are now blended and assimilated into one; and their elementary characteristic features more faintly imprinted. Besides, every one’s experience and observation will instruct him, that in populous kingdomsthose classes branch out into innumerable intermixtures, orders, and genera; and that the species and varieties are as numerous as the individuals of the human race. Amongst the ab-origines, and stationary inhabitants of most kingdoms, there are indeed some prominent features peculiar to each community; which are, in some degree, conspicuous in the corporeal, and still more in the mental outlines. Mankind, exclusive of their original mould, as issued from the mint of the Creator, are afterwards diversified by climate, soil, diet, government, religion, association, occupation, and habit.By Civilization, mankind are arranged and connected into an infinite series of descending and dependent links. In a state of nature there are few gradations in society; few professions or mechanical arts. Mr. Voltaire makes two great divisions of mankind; the oppressors, and the oppressed. Descending the mole-hill and ladder from the throne to the cottage, we may trace a multitude of gradations in the scale of polished communities. We descend thro’nobility and gentry of independent fortunes, in lands or money; through literary professions, including divinity, medicine, law, and various other branches of active or speculative science: all of which united, constitute, even in the most opulent nations, but a small portion of the community. We next descend to a fertile hive of husbandmen and artizans, laborious drudges in mechanical trades, arts, manufactories, and commerce: to a numerous class of retailers or venders of merchandize, and of the necessaries of life: to soldiers, sailors, domestick servants: to no inconsiderable multitude buried under ground, and occupied in digging metals and fuel from the bowels of the earth: to infirm, cripples, diseased, puerperal, aged; and to many other links and gradations, which must be greatly diversified by the variety in governments, religion, climate, national genius, and other causes which will occur to philosophers, and to gentlemen of reflection. It is of essential importance, not only in an enlarged political, but also in a medicinal view, to contemplate these constituent portions of a community.The inhabitants crowded into Cities and towns, and those dispersed in small villages, and in the Country, constitute other large groups of society. If the result of Susmilch’s researches and materials, collected throughout Germany can be depended upon as a criterion for other European nations, the inhabitants in the country are to those in cities and towns as 3½ to 1. Great cities, if we except Rome and Constantinople, are of modern date in most kingdoms of Europe. In the ninth century, a few towns had been built in Germany; but in England, corporations and considerable towns are posterior to the Norman invasion. Cities, associated communities, and towns, during the religious frenzy of crusading, and after the termination of this epidemical distemper, were asylums from aristocratic tyranny; and when of moderate size, are seats of politeness, refinement, emulation, arts, and society; but when overgrown, they check population; they are drains of the human species, the graves of infants, and nurseries of vices. Unfortunately also for succeeding generations, numerous cities, towns, and harbours, have been foundedupon low, unhealthy situations, surrounded by morasses and hills. Most cities seem to have grown to maturity by accident and time: their streets are narrow, irregular, not sufficiently ventilated; and the inhabitants absurdly and perniciously thronged together. There are moderate-sized towns, and even country districts, whose situations are so noxious, as to make the burials exceed the births. We need not travel to new uncultivated continents and islands, nor to rank tropical climates for proofs: we have only to consult Dr. Short’s Registers of several parts in this kingdom.The assemblages of the human race are greatly diversified by their Ages. During nine months only of uterine incubation, and from the most minute tadpole, an infant at birth has grown to between sixteen inches and two feet; and from five to ten pounds in weight. After birth, the increase is slower; and it proceeds to shoot upwards a few inches annually, but not always in successive progression, and to make additions to its weight and dimensions. Between puberty and twenty-one years of age, man hasgenerally attained to the summit of his altitude; females, rather earlier; and those still earlier who inhabit warm climates. Excluding that fragment of pigmy mortals, the Laplanders, between five and six feet in height is the most universal and mean standard of the human race; and their gravity in various gradations, from eight to twenty stone; in both which respects, females usually fall short of males. Nature, however, is not limited to one model of altitude or gravity; she sometimes deviates into extravagancies, producing human giants, from nine, down to diminutive dwarfs of two feet; together with shapeless monsters wallowing in fat, and weighing upwards of forty stone. Let us next endeavour to form arithmetical estimates of the human race, at different ages. Davenant calculates the inhabitants of England (not including Scotland) at five million and a half; and their sundry ages as follows:—Under one year of age, 170,000; under five years of age, 820,000; under ten years of age, 1,500,000; under sixteen years of age, 2,240,000: from sixteen years of age to the extreme of existence,3,260,000; of which number he estimates 600,000, or about one ninth part of the whole community, to have passed sixty years of age; and of which veteran group the males constitute 270,000; the females, 330,000. Dr. Price supposes nearly an equal proportion living under 16, and above that age; but that the latter are the most numerous class: Davenant states the medium at 20. Dr. Halley supposed the number living under 16, to comprize about one third of the community; and also, that those living between 20 and 42, were about one third of the whole. The preceding analysis of the numbers living at different ages in one kingdom, may with facility be applied to any numerical extent. If we wish to calculate the proportion living at similar ages amongst one hundred million, we have only to multiply by 18 each of the preceding groups composing five million and an half of inhabitants.Two large and important classes are formed in society, by the distinction of the Sexes into male and female. So soon as theorgans of generation are completely evolved; that is, when the two sexes arrive at puberty, they are inflamed with a new passion and pleasing sense. In most warm climates, this generative period is somewhat earlier than in northern latitudes; and in the former also, women are said to be more prolifick. We shall therefore devote a few words to the union of the sexes, from whence ensue procreation and births. Some calculators have computed, that amongst five million and an half of inhabitants in England, there are annually about forty-one thousand legal marriages: of which one sixth part are widows and widowers; about one marriage to every one hundred and four inhabitants; and the annual marriages to the births, as 1 to 4, or 4½. The mean ages at which marriages in this island commence, is computed from 32 to 35 on the side of the man, and 25 on that of the woman; but in this estimate, second and third marriages are included.In cities, not only fewer enter into the matrimonial state, but the product also ofcity and country-marriages is observed to differ. Marriages in cities, one with another, seldom produce above four; generally between three and four, and sometimes not three children: whereas country-marriages seldom produce less than four, and generally between four and five. Whether this disparity between the product of city and country-marriages is to be imputed to dissipation, libertinism, and incontinence, both in the single and married state; to the cloudy apprehensions and fears of overstocking their house; to later, fewer, and less frequent unions in the matrimonial bond; or to all these and other causes combined, I submit to the reader’s consideration. From authentick registers of a variety of small towns and country parishes in England, Dr. Short found, that each marriage produced four and a half children, at a medium; for some married pairs have only one or two: others six, eight, twelve, or more; and a small remnant are unprolifick. Natural, or illegitimate children, are enrolled in the public records of christenings, and swell their proportion to the registered weddings somewhat greaterthan they would appear without this extraneous addition. In some German registers, Dr. Short found, that of 333,655 births, the illegitimate amounted to one thirty-seventh part; and in an inland town of England, that of 10,337 births, 284, or about one thirtieth part, were illegitimate.If the number of inhabitants in any kingdom, city, or village, continues the same without increase or decrease, and supported by their own procreation only, it is evident, that there the annual births and burials will be equal, and the supply proportioned to the waste; and in equal numbers, as many will die at all ages as are born in the year, on a general average; and the numbers dying any year at one, two, three years of age, and so on to the extreme of existence, will be just equal with the numbers who successively attain to those different ages at which the others die. The total annual births amongst five million and an half of inhabitants in England, are calculated by Davenant at 190,000; which is about one birth to every twenty-fiveinhabitants; and amongst nine million of inhabitants in Britain and Ireland, the annual procreation will considerably exceed three hundred thousand; and the annual mortality should be somewhat inferior. In the kingdom of Prussia, from the year 1715 to 18, there were christened, at an annual medium, 78,826; buried, 55,852. In the kingdom of Sweden, the annual average of births during nine years, ending in 1763, was 90,240; burials, 69,125. In Norway, in 1761, the christenings were 11,024; burials, 6,926. In France, during three years, ending in 1772, the annual average of births was 920,918; burials, 780,040. In the county district of Vaux, in Switzerland, during ten years, the births were 3,155; burials, 2,504. The country, says Graunt, has 6,339 births for 5,280 burials. In that little fertile atlantic island Madeira, the inhabitants have been computed to double themselves in eighty-four years; so great is the difference between the births and burials. In some provinces of North America, if Dr. Franklin’s calculations are correct, the inhabitants doublethemselves in the short space of twenty-five, twenty-two, and even in fifteen years. On the other hand, in all the large cities of Europe: in Paris, Vienna, Rome, Dresden, Berlin, Amsterdam, London, Edinburgh, Dublin, and in almost all towns of considerable magnitude and population, the total annual births are inferior to the burials. It is calculated, that in London, within the last 150 years, near a million more of the human species have been wasted, beyond what were reared by its own original growth and procreation. But in small villages and country districts, the annual births exceed the burials; and it is from this redundance that a supply is furnished for the extraordinary consumption of armies, navies, war, colonization, emigration; exclusive of sickness, and other morbid casualties: the country and village surplus prevents depopulation.Providence has also wisely ordained, that throughout those European kingdoms, of which we have any registers, a few more Males should be born than Females; andindeed such a surplus is rendered necessary from the waste by wars, emigration, intemperance, mechanical arts, and trades, the inclemency and vicissitudes of the weather and seasons, the vices and misfortunes to which political punishments are annexed; with various other noxious casualties, to all which the male sex are most exposed. In Dr. Arbuthnot’s Table, printed in theLondon Philosophical Transactions, of the proportion between the births of the sexes; in forty-six years were baptized of males, 329,742; of females, 308,644: excess of males only, 21,098. By the London bills, from 1657 to 1776, I find that there have been christened of males, 1,041,149; of females, 983,061, or as 18 to 17: and therefore, that in this long interval of 120 years, and comprehending two million of births, there is only a trifling excess of males, amounting to 58,088: a number which would scarce recruit the consumption of a few active campaigns. The excess of male beyond female births, is not so considerable as books of calculation have represented. In volume the 7th of thePhilosophical Transactionsabridged, there is an account of the annual births during several years at Vienna, Breslaw, Dresden, Leipsic, and Ratisbon: and in those cities, male and female births were as nineteen to eighteen. Amongst the abortives and stillborn, we also find the plurality of males. Lastly, if the registers can be depended upon, it appears that there are more births in Winter than in Summer, both in town and country. But although the fruit of the human womb may not have arrived at maturity before winter, it is no proof against the general law of the spring and summer influence on animals and vegetables, in contributing to fecundity and generation.CHAPTER I.The Comparative Mortality of the Human Species, and of the Sexes at every Age, in City, Town, and Country; and in different Kingdoms of Europe: illustrated with a Chart, and with Tables. The Comparative Mortality of the Human Species, by different Diseases and Casualties: exhibiting a Chart, and Tables of all the Mortal Diseases and Casualties in London during Seventy-five Years: illustrated by and contrasted with the united Observations of Medical Authors, with various Hospital Registers; and with a Variety of Materials, Observations, and Comments of the Author.Thatlearned Physician, Dr. Arbuthnot, in his Preface to Huygen’s “de Ratiociniis in ludo aleæ”, says, There are very few things which we know, which are not capable of being reduced to a mathematical reasoning; and when they cannot, it is a sign the knowledge of them isvery small and confused; and, when a mathematical reason can be had, it is as great a folly to make use of any other, as to grope for a thing in the dark when you have a candle standing by you. Medical writers, almost universally, have neglected, or barely skimmed the surface of the following important subjects. The public registers of births, burials, and diseases, are overlooked by all the modern systematick authors: they leave us equally ignorant of the aggregate, or comparative number, or force of those fiends which haunt and ravage the globe. To speak metaphorically, in medical books, the extensive desolation of the most rapacious tyrants and conquerors are confounded with the uninteresting history, and petty depredations of a robber. The detached observations of physicians, or other literary individuals, confined perhaps to a small town or parish, a meagre detail of village remarks, furnish, in innumerable instances, foundations too slight for the erection and stability of general proportions. In order to form useful tables of the ratio of mortality at various ages, to determine upon the absolute and relative havock by differentdiseases, upon the general effects of climate, season, local situation, diet, drink, luxuries, new customs, and manners, &c. we should extend our views far beyond the narrow bounds of a parish, or even of a province; we should include an interval of many years, collective numbers, and large groups of mankind.It appears to me, that a great number of the fundamental principles, or of the primary orders of medical architecture, have not yet been established, neither in Pathology, to which this Dissertation is chiefly related; and much less in Therapeuticks. The lumber and mountain of ponderous systems, heaped together from Galen to Stahl, can only be compared to Egyptian pyramids. Except what has been done by a few authors, hereafter to be mentioned, the sciences of Medical Arithmetick and Universal Prognosticks, are new in medicine. In emergencies, the constant appeal has been, with oracular reverence, to aphorisms and opinions of individuals. In a word, no medical author has yet attempted to take the gages of life and death, and of morbid devastation, and, in one general survey, to encirclethe horizon of human existence and distempers. I have made some, at least laborious efforts, to rescue a momentous part of active medicine from that conjectural stigma with which the whole profession has been branded in the lump. And, however it may be slighted as an heretical innovation, I would strenuously recommend Medical Arithmetick, as a guide and compass through the labyrinth of Therapeuticks.We are now to view the human race unexpectedly arrested, and struggling in the tragical and last stages of their terrestrial pilgrimage. The vision of human life is soon at an end: we are ushered into the world with lamentable exclamation; and are too often torn out of it in pain and agony. Bills of Mortality, however defective and inaccurate, yet sufficiently demonstrate this awful truth, that very few of the human species die of old age, or natural decay: by far the greater proportion are prematurely cut off by diseases. Of all the animal tribe, who usually bring forth one at a birth, none die in such numbers, in infancy, as the human race. In London, Vienna, Berlin, and every other overgrown metropolis of Europe, on an average, one half of the children born, die underthree years of age. But in country towns and villages, the proportion of infant mortality greatly abates. In some country towns of England, of considerable magnitude and population, as Manchester, half the children die under five; at Norwich, half under six; at Northampton, half under ten years of age. London, therefore, will have lost, out of equal capitals, a number in the intermediate space, between three and ten, more than Northampton.Attend next to the small proportion of Infant Mortality in open country districts. By Dr. Short’s registers of several small country villages in England, the major part born live to 25, 27, 33, and 40. In many healthy country parishes, half the inhabitants born live to mature age; to 40, 46, and a few even to 50 and 60; and rear large families of children. In some extensive country districts of Switzerland, similar observations have been made by Susmilch and Muret. Here, therefore, is an astonishing disparity between the duration of city and country life: but particularly, let it be engraved upon the memory, in the early stages of puerile exigence. Infantsin cities resemble tender delicate plants excluded from fresh air; or fish confined in stagnant putrid water: they perish before acquiring a solidity and seasoning to endure the adulterated quality of the surrounding element; and their thread of life is then suspended by a tender cobweb.Mortality, universally, during the first year after birth, is the most enormous in the funeral catalogue. A London infant at birth, has but an equal chance of living to three years old; whereas in the country, as before observed, half born survive to maturity. Upon reaching the third year, in cities, infants are somewhat seasoned, and the hurricane of puerile carnage is greatly abated. There is not afterwards such a prodigious disproportion between city and country mortality; and, in a few years after, from seven to ten, they approach nearer to an equality. From the London registers of burials, it appears that more die in the metropolis under two years of age, than from two to upwards of forty; and more under five years of age, than from five to between fifty and sixty: yet under five, there are but an inconsiderablenumber alive, compared to the latter class above that age: the deaths are greatly disproportioned to the living numbers or capitals. A few more die in the short interval between five and ten years of age, than in the succeeding double interval from ten to twenty. Between eight and sixteen years of age, one of every seventy of the Christ School boys is computed to die. Davenant rates the decrement in these years at only oneper cent.After reaching the tenth year, the torrent of mortality in city, town, and country, is subsided; and during the next eight or ten years of adolescence, very few die. From seven to ten, may be termed the highest pinnacle: having surmounted all the dangers and precipices of the early preceding journey, there is no stage wherein the future prospects of existence and longevity are so extensive. From birth to ten, the tide of life continues in annual gradation to increase; and from ten to the ultimate verge of existence, vitality continues gradually to ebb. Between twenty and thirty, more die in London than in the fifteen preceding years; and the burial list continues turgid to sixty; at which latter stage, the mortality is computed between four and fivepercent.One reason, but not the only one, as I shall hereafter prove, of the great surge in the London bills, from twenty up to forty, is, that within this interval of life, the majority of the new settlers or recruits, arrive; and consequently augment the burials, from twenty to forty, beyond their natural proportion. After passing the meridian, and in the evening of life, the seasoned inhabitants of cities are said by Dr. Price, to have the advantage of the country, in health and longevity: that is to say, although the number who have survived in the country to sixty, seventy, and eighty, are greater proportionally than in cities, yet the latter class arrived at those years in London, have, comparatively, surer expectations of life. I do not, however, find this assertion verified in fact; the balance, if any, vibrating alternately on each side. The proportion of inhabitants who reach eighty years of age are computed, in London and Vienna, at one of every forty: but in country parishes, at one of every twenty-two; and in some, even one of every eleven. In both city and country, the few survivors at ninety, out of each thousand cœtaneous births, will have lost almost all theirfellow-travellers in the journey, long before reaching that goal; and about three or four only out of each thousand, on an average, will be then left alive.There are a few instances of extraordinary Longevity, to 150 and 165; such are Jenkins and Par, in this island. In Bacon Lord Verulam’s History of Long Livers, male and female; their climate, diet, mode of life, appetites, exercises, studies, passions, dispositions, habits, and complexions, were exceedingly dissimilar. It is however probable, from observation and analogy, that the indigent and laborious class of mankind do not attain to longevity in the same proportion with the middling and more opulent ranks. The wandering Savages of America are notoriously short-lived. Throughout Europe, Asia, Africa, and America, the rich, the poor, the inhabitants of city and country, with very different complexion, climate, soil, diet, and conveniences, all seldom exceed the usual term of life allotted to man: seventy and eighty is mentioned in holy writ, as the brink of our earthly duration. Since the days of Moses; that is, between three and four thousandyears, human existence has been circumscribed within the same narrow bounds. In the London registers of mortality, during a period of thirty years, from 1728 to 1758, the total mortality is 750,332; and of all this number, 242 only reached beyond 100 years of age; one of whom arrived at 138. In some races and families of men, longevity seems to be hereditary; and his age, though little more than a dream, exceeds that of all other living creatures, a few only excepted. Amongst the quadruped creation, the elephant surpasses man in longevity: amongst the birds, the Swan, and a few others, have survived upwards of a century. The age of fishes is determined with more ingenuity than certainty: some seem to rival man in years. Among the numerous vegetable tribes, the Oak, Chestnut, and some other great trees, survive centuries.On contrasting the mortality of Males and Females, it appears, that, notwithstanding the surplus of male births, the perils of childbearing, the many vexatious diseases peculiar to the fair sex, and that physicians and apothecaries have many more patients of the latter; yet the total aggregate number of livingfemales exceeds that of males, in most European kingdoms. Upon a numerical inquest in Edinburgh, and some other great cities, it was found, that females were to males as 4 to 3: in London, as 13 to 10; and in some other cities and towns, as 9 to 8. But in country districts, Graunt and Susmilch agree, that the two sexes approach nearer to an equality. In the province of Jersey, in North America, the males were found the majority. From 1702 to 1752; that is, during a period of fifty years, I find the proportion of male and female mortality in London as follows: Male deaths, 618,076; Female deaths, 626,692. Whence, therefore, does it happen, that female deaths preponderate over the male, when more of the latter are born, and, as calculators assert, the mortality of males, at all ages, is greater than that of females? As a solution of this difficulty and partial exception, I should suggest a greater exportation and transportation of males to the sea and land service, to nautical commerce, and to unhealthy climates.Even in the Marriage State, the chance of survivorship seems considerably in favour ofthe wife. In Breslaw, during eight years, five married men died to three married women. Susmilch, on a scrutiny through several kingdoms and principalities of Germany, found, that three married men died to two married women. Dr. Price estimates the chance in favour of the wife being the survivor in marriage, as 3 to 2: and this calculation is confirmed by the experience of the general Clerical Society in Scotland, who have long established funds to support their widows. From their records, it appears that twenty married clergymen have died to twelve wives; or, as 5 to 3. By an accurate survey of several principalities and cities in Germany, and collected by Susmilch, the widows were to the widowers as 3, and even 4 to 1. At marriage, it should be observed, there is generally a disparity of age; the bridegroom is from six to twelve years older than the bride; and therefore should, in the course of nature, die sooner: and perhaps also more widowers, comparatively with the other sex, enter into a second marriage; which tends to reduce their numbers. Besides, husbands are more exposed to the vicissitudes of the weather and seasons, to excessive labour and noxious trades, and tomany other causes of diseases. Dr. Price finds, that the sexes respectively commence to be widowers and widows about 52 and 44; that is, men and women entering into matrimony, on a general average, at the age of 33 and 25, will become widowers and widows at 52 and 44: consequently, that each marriage will be dissolved by the death of one of them, in nineteen years; which is the ultimate term and probability of the husband and wife being both alive. For although some marriages may be protracted forty and fifty years, yet others may be dissolved in one year, or in a shorter time.We have not yet sufficient information to determine the comparative chances of Female Longevity in the married and single state. At Berlin, indeed, calculators have remarked, that there were more married women alive at great ages, than of those who remained single. But such result might naturally be expected from a greater proportion in the decline of life of widows and wives, compared to antiquated virgins. From the ages of fifteen to twenty-five, married women likewise are said to have the advantageof the single, in whom the dictates of nature are frustrated and violated.Comparing the mortality of the Seasons, Dr. Short found, from a variety of country-registers, that mortality generally begins its reign in December; that at March it is in its zenith; and at May in its declension. In twenty-five country towns and parishes, he found the winter to the summer mortality as 50 to 41. At Manchester, a country town of England, Dr. Percival found the winter to the summer mortality as 11 to 8. At Vevey, in Switzerland, during sixty years, Mr. Muret found the burials, during the four winter months, as 5 to 4 to those of the summer. Another proof of this is recorded in theRecherches sur la Population, par Messance: The total sick admitted into theHotel Dieuhospital in Paris, from 1724 to 1763 (forty years) were, in the four winter months, December, January, February, and March, 314,824; and in the four summer months, June, July, August, September, 238,522; or as 4 to 3. In London too, the undertaker’s, harvest is in winter. There is one obvious reason why, in every metropolis, thewinter mortality should exceed that of summer, from the greater concourse of inhabitants of all ranks: but, independent of additional population in winter, the same law seems to prevail in country places. In a subsequent part I shall attempt to throw some collateral illustration upon the subject.Let us close this humiliating scene with a general abstract of human carnage. If we scan the dolorous mansions of disease, we find, on an average, 1 death, annually, out of every 5 families in cities: but in country towns, and open districts, 1 of 7, 8, 9; and in a few healthy places, 1 of every 10 families. Including the whole assemblage of inhabitants in city, town, and country, from birth to the extreme of existence, they are computed to die in the following annual proportion to the living: In London, 1 of 21; Dublin, 1 of 22; Edinburgh, 1 of 21; Vienna, 1 of 20; Amsterdam, 1 of 22; Berlin, 1 of 26. This is nearly Dr. Price’s calculation; but Halley and Susmilch compute only 1 of 22 to 29 to die annually in cities. In smaller cities and towns, such as Norwich and Northampton, the generalaverage of deaths is 1 of 24 to 26; but in several provinces and healthy country villages, 1 of 32 and 33, up to 45, 50, and even 60, is the annual drain: 1 of 43 to 50 was the average in upwards of a thousand country parishes on the continent; and recorded in Susmilch. Within the above short intervals of time, there will have died in the respective cities and country places enumerated, a number equal to the whole inhabitants. But the annual decrease of the oppressed Negroes, in the West India islands, is estimated at 1 of 7.The ancient Egyptians allotted 3 generations to a century, which is bordering upon the truth; at this day, 1 of 32 and 33 up to 35, is near the measure of a generation, and to the general decrease of a community throughout Europe, comprehending all the inhabitants in city, village, and country: that is, mankind share amongst them from about 32 and 33 to 35 years each of existence: and within this fugitive interval of time, a number equal to all the present inhabitants of this island, or of the whole earth, will be exterminated. If we extend this estimateto the whole human race, eight hundred million will die in 33 years; about twenty-eight million annually; seventy or eighty thousand daily; about three thousand hourly; and from fifty to sixty every minute. It is perhaps superfluous to add, that, in the same intervals, an equal or superior number will be born.According to De Moivre and Dr. Price, “the probabilities or expectation of life, decrease as we advance from childhood to old age, in an arithmetical progression; that is, in such a manner that the difference is always the same between the number of persons living at the beginning of any one year, and the number living at the beginning of the following year.” Or, in other words, less enveloped in mathematical obscurity, out of any specified number, an hundred or a thousand, the same proportion will continue to die every year until near 80 years of age and upwards: consequently, the probabilities of life are constantly decreasing; because notwithstanding the progressive annual drain from the capitals, yet the deaths continuethroughout equal. But this proportion is certainly erroneous in the first stages of life, and until about 10. View the above proposition in another light.From any given number there will be an equal drain annually, until what De Moivre terms thecomplementormaximum, or utmost probable extreme of life, which he fixes at 86, all are dead. The probability, therefore, that the whole of any limited number whatsoever, or age, will all be exterminated is the number of years between 86 and the year such a number are all alive. Of 56 persons alive at 30, they should all be dead in 56 years, because 56 added to 30 amounts to 86, the maximum: of 46 persons alive at 40 years of age, they should all be dead in 46 years: and 36 persons alive at 50 years of age, should be dead in 36 years; for 50 and 36 complete the maximum. Again, the expectation of any single life is only half the maximum or complement, or half the space between that age and the ultimate term of existence: but here we must repeat the former exception, and draw the line after 10years of age. The expectation of two equal joint lives, according to De Moivre, is one third of the complement of life. Example: two lives, aged 40, have an even chance or probable prospect of continuing together in exigence only 15 years; which is the third of the complement, reckoning from 40 to 86: the expectation of the survivor is also 15. Or, suppose a lot of marriages of persons at 40 years of age, they will, on an average, continue together 15½ years; and the survivors the same time after. This expectation, therefore, is the probable duration of each marriage, and the share of each person’s life. But it may be proper to add, that the duration of marriages, and the value of single and joint lives, will, on a promiscuous calculation, be different from the registers of annuitant and insurance offices; because they are scrupulously vigilant to exclude all diseased and unhealthy persons from becoming members.The following Chart and Tables, present a distinct prospect of the fates clipping the mortal thread, from birth to old age, incity and country. But we are not to suppose that in every instance there will be annually a regular arithmetical diminution, as marked in the different tables: some years will be more fatal than others; and we are to form estimates from an average of several years. The first column points out the age, the second the number living at that age, the third the number who die during the year; and so on to the end of the table. But observe, that the number of infants, at the beginning of the second column, are supposed to be all born together on the first day of that year; and this rule applies throughout all the remaining ages. The two short tables of 15 and 30 years mortality in London, demonstrate the gradations at longer intervals than a single year. From these different tables may be estimated the annual waste, out of any specified number, at all ages, the ultimate prospects of existence, and the odds or probability of a person in health surviving a stated number of years.A GENERAL CHART, with different Tables,Exhibiting the Gradations of Mortality in City and Country.Shewing the Probability of the Duration of Life inLondon, deduced by Mr. Simpson, from Observations on the Bills of Mortality in London for Ten Years, from 1728 to 1737. The total Number of Inhabitants, probably, about 650,000 in Winter. One Half born died under Three Years of Age.

AComparative View,&c.

A Sketch of our Planet’s Station, Rotation, and Rank amongst the other Celestial Orbs; and of its Investing Elements:—of the Habitable Parts of our Planet: the Number of the Human Species, and their Division into various Classes, Genera, Groups, and Gradations: their Comparative Births.

Thereare two methods of promoting Medical Knowledge: one by negative information, or criticisms on the numerous errors of preceding authors: the other by direct instruction, and improvement on former models. The first method is wornout in hackneyed chimes: the second is encumbered with infinitely more difficulties; and its merits paramount in the superlative degree. However unequal I have imposed upon myself the latter task. But, previous to the discussion of the general theme, it will conduce to order, and to the anticipation of explanatory digression and illustration, to glance at the station, rotation, and rank of our Parent Planet amongst the other celestial orbs; at its investing elements; and at the number, groups, and recruit of mankind. A navigator or historian, who undertakes the description of any island, kingdom, or continent, commences with their geographical outlines and climate, penetrating afterwards thorough a scrutiny of the inhabitants. Upon a similar, but more majestic model, our Introductory Preface is founded. Throughout the whole of this intricate, sublime, and inexhaustible subject, if I do not delay sufficient time to fix, I shall at least hope to start the reader’s attention to a variety of grand objects, inseparable from a comprehensive knowledge of Medicine; and of which I shall touch the fundamental keys and chords.

consists of the Sun, of seven Planets surrounded by ten or more Moons, and of the Comets. The other siderial lights with which the vault of Heaven is studded, and which are denominated Fixed Stars, have a very distant affinity with our planetary sphere: they are infinitely too remote to be enlightened by our luminary; and therefore astronomers, with good reason, imagine each star to be a sun to encircling planets, though invisible to us; and to constitute throughout boundless space thousands, or perhaps millions, of habitable worlds. Numbers of those stars, most luminous and proximate, are arranged into arbitrary clusters, called Constellations, or Signs; and serve to mark the several stages of the rotating orbs in our system.

The Sun, whose magnitude far surpasses that of the seven planets united, is placed in the center, suspended in the immense celestial expansion and firmament. Surrounding him, at different distances, and in the following order, are the planets Mercury, Venus, the Earth, Mars, Jupiter, Saturn, Georgium Sidus. These planets are incessantly revolving from west-by-south to east, and within certain intervals of time, make a complete circle round the Sun; which is the length of each planet’s year; and is larger and longer in proportion to their respective distances. The velocity of their revolution in their annual orbits, together with their gradations of light and heat, are also in proportion to their solar proximity. From the Sun, the Planets, with their surrounding moons, derive heat and light; and when this is intercepted by any planet, or its satellite, an eclipse or darkness ensues. In what periods those tremendous celestial bodies, named Comets, revolve round the Sun, is not yet exactly adjusted.

One of the seven planets, the Earth, this small domain of restless mortals, and to which all our future observations shall be directed, is distant from the Sun 95,173,000 miles. In shape, it has more resemblance to a turnip than to a globe. Its diameter is 7,970 miles: its circumference 360 degrees; which amounts to 24,840 English miles. Geographers divide the globe of ourplanet into two equal parts, or hemispheres, the northern and southern, by an imaginary girdle, or ring, named the Equator. Two other imaginary girdles surrounding the earth, and distant from the equator on each side 23½ degrees, north and south latitude, are named the Tropicks of Cancer and Capricorn; comprehending between them the torrid zone. From these tropical circles the zones, called Temperate, extend on each side 43 degrees: and at their extreme boundaries, we reach the polar circles 23½ degrees distant from each pole. The north and the south poles are in the middle of each hemisphere of the earth; and the distance of each from the equator is 90 degrees.

The earth has several incessant motions: one in which it turns, like a suspended wheel upon its own axis, from west to east, every twenty-four hours, which is the length of its day and night: the second, where it is rolling progressively in its great annual circle, or journey round the Sun: the third, the alternate inclination of itspoles towards the sun at different times of the year: the fourth, the small circle which it describes monthly round the common center of gravity, or balance, with its moon. The earth’s diurnal revolution upon its axis, is at the rate of fifteen degrees, or 1,035 miles hourly. But the rapidity with which it is whirled in its annual orbit, is, hourly, 68,243 miles: whereas the swiftness of a ball discharged from a cannon is, in the same time, only 480 miles. Projected through the vacuity of heaven with this amazing velocity, in the space of 365 days, 5 hours, and 49 minutes, the earth completes its annual circle; which is the length of our year. The earth’s rotation every twenty-four hours upon its axis, is the cause of day and night, or of light and darkness. In this successive rotation, one half of its globular surface is always enlightened; the other half being then obscured in nocturnal gloom, except when enlivened by the reflected rays of the moon, or of one of the planets, or by the fainter glimmering of the fixed stars. The alternate spiral inflection and declination ofthe earth’s poles during its annual journey round the Sun, is the cause of the different lengths of Days and Nights; of the Seasons; of Summer and Winter; of the Equinoxes, and Solstices: and as each pole inclines or recedes, it is summer and winter, alternately, in their respective hemispheres. The effects of this compound terrestrial circumvolution on the animal and vegetable creation, would alone be a magnificent theme for many volumes.

One Moon only is allotted to our earth; from which it is distant 240,000 miles. The moon’s diameter is nearly one fourth less than that of the earth, which it obsequiously accompanies throughout its annual circuit; and round which it makes a perpetual revolution, from west to east, every lunar month. The constant agitation and periodical surges of the ocean, are greatly influenced by the moon, assisted, however, by the centrifugal force of the earth’s motion. It is also ascertained, that in some diseases, the human body is considerably under the lunar influence; and its energy is still more conspicuousat periodical changes, during the month and the year. Many arguments might be suggested to invalidate and overturn the ancient astrological systems, and to prove that the celestial influences upon us are not, in any considerable degree, derived from sources more remote than the solar confines.

The first Element in pre-eminence and subtility, without which all would be lifeless chaos in our system, is Heat and Light. Cold is a negative quality, and merely a comparative diminution of heat. The middle regions of the earth being repeatedly more exposed to the Sun’s vertical rays, are consequently most heated and scorched. From the equator to the poles, are all the gradations of heat and cold; but for reasons too prolix to enumerate, these gradations are not in exact measurement with the geographical distances from the equator; neither in the same continent, nor in different continents. By the scale of Farenheit’s thermometer, water boils at 212, freezes at 32; and blood-heat, or that of the human body,is about 97. The most intense heat of the tropical regions, as measured by the same thermometer, is frequently many degrees above the human temperature; and the most intense cold of the polar regions, often many degrees below 1 or 0 of the same scale. Neither of these noxious extremes of pestilential heat, nor of deadning blasts from boreal snow, could be long endured by the human species, were their bodies not protected and skreened by fences of nature or of art. Atmospheric heat, equal even to that of the human body, is felt intolerably scorching and suffocating. Every one also knows, by personal experience, that in different latitudes, and in summer and winter, the degrees of heat and cold, the duration, recurrence, and changes, are extremely variable. But within the equatorial limits, these variations are much less conspicuous, both in the thermometer and barometer. From this main spring and soul of animated nature, blessings and bounties are diffused, in thousands of channels, to every order of the creation; and from its extremes and vicissitudes, a multitude of evils and diseases are inflicted upon man.

Between the earth and celestial vacuum is interposed an element, called the Atmosphere, or Air. This invisible elastic fluid is floating equally round our planet, to the distance of at least forty-five miles perpendicular elevation. It has been compared by some philosophers, to packs of wool heaped on each other: that nearest the ground is most dense, compact, and ponderous; and as we ascend, it becomes gradually more rare, light, and cold. The prodigious gravity, or pressure, of this atmospherick column, appears incredible to those who are ignorant of experimental philosophy, and of the air-pump and barometer. Upon a man’s body, of middle stature, its weight is equal to thirty-two or thirty-three thousand pounds: but in rainy and variable weather, and especially on the summit of high mountains, there is a diminution in its pressure of many thousand pounds. This great mass of air, as well as the waters of the ocean and of rivers, is in constant agitation; sometimes gliding in gentle calms; sometimes, with wild uproar, raging in storms and hurricanes, and dispersedin a variety of currents, over different parts of the earth and ocean in Winds, constant, periodical, variable, and irregular. Without the concurrent support of air, animal and vegetable life would soon be annihilated. On them great and sensible effects are produced by the atmosphere and winds: by the air’s noxious impregnation, stagnation, want of elasticity, heat, cold, moisture, dryness; by the points from whence winds blow, their constancy, irregularity, recurrence, velocity.

The earth is the cistern, and one principal fountain of another still grosser element. From the Sun’s heat, and from the successive streams of air and winds, a prodigious evaporation is carried on from the surface of the ocean, from the land, and from vegetables. Whether part of the atmospherick air is also converted into vapour, is a question too intricate and diffuse for our present inquiry. The critical analysis and history of a single element, would alone far exceed the limits of this Dissertation. It is sufficient for us to observe, that these vapours, terrestrial and aerial, are collected intoclouds, condensed, and again discharged upon the earth in Dews, Mists, Fogs, Rains, Snow, and Hail. The precipitation likewise of this accumulated vapour upon different parts of the globe, is periodical, regular, and variable. In quantity, duration, recurrence, and extent, these aqueous modifications are greatly diversified by the climate and soil, the vicinity to mountains and sea-coasts; the points from whence winds blow; and by many other causes, of which a detail cannot be here expected. From this source also ensue salutary and baneful effects, innumerable to animal and vegetable life.

Another subtile and active agent in the secret machinery of nature, is the Electrical Emanation; which, somewhat perhaps analogous to the aqueous evaporation and congestion before mentioned, is collected into clouds, and, with loud explosion, again discharged and dispersed into the air and earth: the fabulous thunderbolts and artillery of Omnipotence.

We now alight upon that solid mass, Earth, the most fixed and substantial of allthe elements. The surface of our planet is composed of dry land and water; of which the ocean, without including lakes and rivers, occupies by much the largest extent. But the partition of the dry land into four continents, Europe, Asia, Africa, and America, is not well founded. Nature has in reality formed only three great insulated continents, exclusive of the smaller islands. Europe and Asia are contiguous, and cemented together as England and Scotland; or as France and Germany; and their boundaries artificial: whereas Africa, except the slender neck of land near Alexandria, is surrounded by sea. Of these four continents, Europe is the most diminutive. Asia and America stand dignified, above all the others, in superior magnitude. The dry land in Europe, Asia, and America, stretches to a great northern latitude, considerably within the arctick, or polar circles; and, spreading also in that part to a wide extent, east and west, forms nearly a complete bridge between Asia and America. Within the tropical circles are included the belly and bulge of Africa, and of SouthAmerica, with a considerable portion of the broken southern extremities of Asia; together with most of the principal islands in the Pacific and Atlantic oceans. In all the hemisphere south of Capricorn, the land is greatly disproportioned to the ocean. The conical south point of America is but 55, and that of Africa only 35 degrees distant from the equator. A vast orbicular segment of this extreme of our planet, furnishes habitation for fishes only. The dry land is also diversified by elevations and plains; but in no part of the earth’s circumference do those stately monuments of nature’s workmanship ascend to five miles perpendicular elevation.

The Creator has bountifully stored the earth and the ocean with animals and vegetables. Our attention is here circumscribed to the most exalted class, the Human Species; leaving to the naturalist a description of quadrupeds, birds, fishes, insects, and vegetables. By far the largest proportion of the human species are stationed to the north side of the equator, and even to the north of the tropick of cancer. The populous continentsof Europe and Asia, comprehending most of the powerful kingdoms in our planet, are in the northern hemisphere. Within the tropical circles and furnace of the earth, are stationed the next considerable hive of mankind. To the south of Capricorn there are few inhabitants. Some wretched human beings are also scattered through those dreary wastes of ice and snow within the northern polar circles.

Calculators differ enormously respecting thenumber of the Human Species. Some sink the collected herd so low as three hundred million, whilst others exaggerate them to treble and quadruple that amount. It forms no part of my scheme to investigate the comparative population of the earth, one, two, and three thousand years ago. Europe, in all probability, since the era of Roman grandeur, has, together with advancement in civilization, likewise added to the number of its inhabitants. Those parental nurseries of the arts and sciences in Asia and Africa, have no doubt undergone various revolutions in population. If we were to draw any inferences from the numerousAsiatic armies, during the successive despotism of Assyrian, Babylonian, Medean, and Persian monarchies, we should conclude that, in remote ages, the south of Asia abounded in men. The extensive empire of China, at this day, resembles an industrious beehive, and is gorged with mankind. We have still more aversion to plunge into the mysterious archives of Africa, and with critical affectation to pronounce upon the population of that quarter before the decay of its political, commercial, and literary fame with Thebes, Carthage, and Alexandria. That modern-discovered transatlantic continent, from the cruelties and desolation of its first conquerors, and of a loathsome infectious disease exchanged for another, has probably suffered considerable diminution of its original feeble hive, notwithstanding the recruit from Europe; and in the scale of population, as yet ascends to a very subordinate rank amongst the other continents. The most probable calculations estimate the whole human race at eight hundred million: of which number, Europe boasts of little more than one hundred million. The great swarm is in Asia; amounting tobetween four and five hundred million. Africa is supposed to contain one third or fourth of the latter number. Over the fertile wilderness of America are scattered not altogether twenty million.

But if in London alone, where registers of various kinds may be consulted, calculators are, notwithstanding, at variance respecting its population upwards of one hundred thousand, and in the whole island more than a million; it may be reasonably suspected, that in forming a gross estimate of the aggregate terrestrial inhabitants, we may err perhaps, one, two, or even three hundred million. As well might we expect a correct list of the lions, crocodiles, and monkies of Africa, as of the outcast human race in those burning and illiterate regions. To determine the exact amount of inhabitants in any civilized kingdom, the most certain method would be, to make an universal and arithmetical numeration throughout every dwelling. This is often done in several kingdoms; and in none more culpably neglected than in this island. English calculators, therefore, have been under thenecessity, by other laborious processes, to form at least plausible conjectures of the national population. One of their methods is, by collecting the number of houses, and allotting five, or four and a half inhabitants to each house; which, at a general medium, was found near the standard of truth, in a multitude of large towns and open districts in England, Holland, Germany, Switzerland, and Italy; as may be seen recorded in the writings of Short, Susmilch, Price, and many others. In some particular cities, however, such as Berlin, Vienna, Paris, and Edinburgh, where several families are crowded into one house, this rule would lead into error. Besides, in ours, and many other large kingdoms, we are not yet supplied with an authentick register of all the dwellings. And in Asia and Africa, whose political institutions and customs are so different from us, this scale of mensuration may be still more erroneous. Another method, but still more complex and uncertain, of computing the population is, by the annual christenings and burials. When these are equal, and consequently there is no increase or decreaseof the inhabitants, we are directed to multiply the usual prospect or decrement of life, or in the mathematical phrase, the expectation of an infant at birth in that city, town, or district, by the general medium of christenings; which will be the total local amount of the inhabitants. But as the christenings and burials are rarely equal, or a correct list of either can be ascertained from the imperfect registers, this process is very defective.

The Multiplication of the human species depends greatly on society. There are more inhabitants concentrated into one large metropolis of Asia or Europe, than could be collected in many thousand miles of the North-American wilderness on its first discovery. The population of the earth is by no means regulated by the extent of country. If, on the one hand, high refinement and large cities are obstacles to population, a wild state of nature is still more detrimental. A few tribes of North American natives, prowling like hungry wolves, can scarce find precarious subsistence in a wide extent of uncultivateddesarts. Their infants, from necessity, are suckled several years; and after rearing two or three, the period of propagation is nearly over. A medium state between the vicious extremes of refinement and rude savageness; or the middle stages between the iron and golden ages of the ancient philosophers, is most favourable to the increase of our species. But the causes conducive to population and depopulation, are of infinite compass; and are of a compound nature, medical and political. They are connected with the state of government, religion, climate, genius, industry, riches, poverty, taxes, luxury, refinement, wars, colonization, emigration, commerce, agriculture, the unequal distribution and monopoly of property and farms, the plenty, scarcity, and cheapness of food; and, with many other causes, closely allied to our future medicinal investigation. Under governments and nurture, directed with political and moral, together with medical prudence and circumspection, the earth and ocean would probably afford ample nutriment, and their population might be multiplied to three times eight hundred million.

Extending our views over the surface of the globe, we perceive striking distinctions between the human species; not only in the four great continents, but also in different parts of the same continent. These differences are principally manifest in the colour of the skin; in the complexion, countenance, physiognomy, hair, form, and stature. We attend here merely to corporeal distinction, without including the intellectual. These great Classes of mankind may be divided into the Laplander, the Tartar, the Chinese, the European, the African-negro, and the native American. The modern-discovered inhabitants in the islands of the Pacific ocean, seem to have no remarkable cast of countenance or figure to sever them into a separate class. But throughout a considerable extent of the globe, from conquest, emigration, colonization, and commercial intercourse, many nations are now blended and assimilated into one; and their elementary characteristic features more faintly imprinted. Besides, every one’s experience and observation will instruct him, that in populous kingdomsthose classes branch out into innumerable intermixtures, orders, and genera; and that the species and varieties are as numerous as the individuals of the human race. Amongst the ab-origines, and stationary inhabitants of most kingdoms, there are indeed some prominent features peculiar to each community; which are, in some degree, conspicuous in the corporeal, and still more in the mental outlines. Mankind, exclusive of their original mould, as issued from the mint of the Creator, are afterwards diversified by climate, soil, diet, government, religion, association, occupation, and habit.

By Civilization, mankind are arranged and connected into an infinite series of descending and dependent links. In a state of nature there are few gradations in society; few professions or mechanical arts. Mr. Voltaire makes two great divisions of mankind; the oppressors, and the oppressed. Descending the mole-hill and ladder from the throne to the cottage, we may trace a multitude of gradations in the scale of polished communities. We descend thro’nobility and gentry of independent fortunes, in lands or money; through literary professions, including divinity, medicine, law, and various other branches of active or speculative science: all of which united, constitute, even in the most opulent nations, but a small portion of the community. We next descend to a fertile hive of husbandmen and artizans, laborious drudges in mechanical trades, arts, manufactories, and commerce: to a numerous class of retailers or venders of merchandize, and of the necessaries of life: to soldiers, sailors, domestick servants: to no inconsiderable multitude buried under ground, and occupied in digging metals and fuel from the bowels of the earth: to infirm, cripples, diseased, puerperal, aged; and to many other links and gradations, which must be greatly diversified by the variety in governments, religion, climate, national genius, and other causes which will occur to philosophers, and to gentlemen of reflection. It is of essential importance, not only in an enlarged political, but also in a medicinal view, to contemplate these constituent portions of a community.

The inhabitants crowded into Cities and towns, and those dispersed in small villages, and in the Country, constitute other large groups of society. If the result of Susmilch’s researches and materials, collected throughout Germany can be depended upon as a criterion for other European nations, the inhabitants in the country are to those in cities and towns as 3½ to 1. Great cities, if we except Rome and Constantinople, are of modern date in most kingdoms of Europe. In the ninth century, a few towns had been built in Germany; but in England, corporations and considerable towns are posterior to the Norman invasion. Cities, associated communities, and towns, during the religious frenzy of crusading, and after the termination of this epidemical distemper, were asylums from aristocratic tyranny; and when of moderate size, are seats of politeness, refinement, emulation, arts, and society; but when overgrown, they check population; they are drains of the human species, the graves of infants, and nurseries of vices. Unfortunately also for succeeding generations, numerous cities, towns, and harbours, have been foundedupon low, unhealthy situations, surrounded by morasses and hills. Most cities seem to have grown to maturity by accident and time: their streets are narrow, irregular, not sufficiently ventilated; and the inhabitants absurdly and perniciously thronged together. There are moderate-sized towns, and even country districts, whose situations are so noxious, as to make the burials exceed the births. We need not travel to new uncultivated continents and islands, nor to rank tropical climates for proofs: we have only to consult Dr. Short’s Registers of several parts in this kingdom.

The assemblages of the human race are greatly diversified by their Ages. During nine months only of uterine incubation, and from the most minute tadpole, an infant at birth has grown to between sixteen inches and two feet; and from five to ten pounds in weight. After birth, the increase is slower; and it proceeds to shoot upwards a few inches annually, but not always in successive progression, and to make additions to its weight and dimensions. Between puberty and twenty-one years of age, man hasgenerally attained to the summit of his altitude; females, rather earlier; and those still earlier who inhabit warm climates. Excluding that fragment of pigmy mortals, the Laplanders, between five and six feet in height is the most universal and mean standard of the human race; and their gravity in various gradations, from eight to twenty stone; in both which respects, females usually fall short of males. Nature, however, is not limited to one model of altitude or gravity; she sometimes deviates into extravagancies, producing human giants, from nine, down to diminutive dwarfs of two feet; together with shapeless monsters wallowing in fat, and weighing upwards of forty stone. Let us next endeavour to form arithmetical estimates of the human race, at different ages. Davenant calculates the inhabitants of England (not including Scotland) at five million and a half; and their sundry ages as follows:—Under one year of age, 170,000; under five years of age, 820,000; under ten years of age, 1,500,000; under sixteen years of age, 2,240,000: from sixteen years of age to the extreme of existence,3,260,000; of which number he estimates 600,000, or about one ninth part of the whole community, to have passed sixty years of age; and of which veteran group the males constitute 270,000; the females, 330,000. Dr. Price supposes nearly an equal proportion living under 16, and above that age; but that the latter are the most numerous class: Davenant states the medium at 20. Dr. Halley supposed the number living under 16, to comprize about one third of the community; and also, that those living between 20 and 42, were about one third of the whole. The preceding analysis of the numbers living at different ages in one kingdom, may with facility be applied to any numerical extent. If we wish to calculate the proportion living at similar ages amongst one hundred million, we have only to multiply by 18 each of the preceding groups composing five million and an half of inhabitants.

Two large and important classes are formed in society, by the distinction of the Sexes into male and female. So soon as theorgans of generation are completely evolved; that is, when the two sexes arrive at puberty, they are inflamed with a new passion and pleasing sense. In most warm climates, this generative period is somewhat earlier than in northern latitudes; and in the former also, women are said to be more prolifick. We shall therefore devote a few words to the union of the sexes, from whence ensue procreation and births. Some calculators have computed, that amongst five million and an half of inhabitants in England, there are annually about forty-one thousand legal marriages: of which one sixth part are widows and widowers; about one marriage to every one hundred and four inhabitants; and the annual marriages to the births, as 1 to 4, or 4½. The mean ages at which marriages in this island commence, is computed from 32 to 35 on the side of the man, and 25 on that of the woman; but in this estimate, second and third marriages are included.

In cities, not only fewer enter into the matrimonial state, but the product also ofcity and country-marriages is observed to differ. Marriages in cities, one with another, seldom produce above four; generally between three and four, and sometimes not three children: whereas country-marriages seldom produce less than four, and generally between four and five. Whether this disparity between the product of city and country-marriages is to be imputed to dissipation, libertinism, and incontinence, both in the single and married state; to the cloudy apprehensions and fears of overstocking their house; to later, fewer, and less frequent unions in the matrimonial bond; or to all these and other causes combined, I submit to the reader’s consideration. From authentick registers of a variety of small towns and country parishes in England, Dr. Short found, that each marriage produced four and a half children, at a medium; for some married pairs have only one or two: others six, eight, twelve, or more; and a small remnant are unprolifick. Natural, or illegitimate children, are enrolled in the public records of christenings, and swell their proportion to the registered weddings somewhat greaterthan they would appear without this extraneous addition. In some German registers, Dr. Short found, that of 333,655 births, the illegitimate amounted to one thirty-seventh part; and in an inland town of England, that of 10,337 births, 284, or about one thirtieth part, were illegitimate.

If the number of inhabitants in any kingdom, city, or village, continues the same without increase or decrease, and supported by their own procreation only, it is evident, that there the annual births and burials will be equal, and the supply proportioned to the waste; and in equal numbers, as many will die at all ages as are born in the year, on a general average; and the numbers dying any year at one, two, three years of age, and so on to the extreme of existence, will be just equal with the numbers who successively attain to those different ages at which the others die. The total annual births amongst five million and an half of inhabitants in England, are calculated by Davenant at 190,000; which is about one birth to every twenty-fiveinhabitants; and amongst nine million of inhabitants in Britain and Ireland, the annual procreation will considerably exceed three hundred thousand; and the annual mortality should be somewhat inferior. In the kingdom of Prussia, from the year 1715 to 18, there were christened, at an annual medium, 78,826; buried, 55,852. In the kingdom of Sweden, the annual average of births during nine years, ending in 1763, was 90,240; burials, 69,125. In Norway, in 1761, the christenings were 11,024; burials, 6,926. In France, during three years, ending in 1772, the annual average of births was 920,918; burials, 780,040. In the county district of Vaux, in Switzerland, during ten years, the births were 3,155; burials, 2,504. The country, says Graunt, has 6,339 births for 5,280 burials. In that little fertile atlantic island Madeira, the inhabitants have been computed to double themselves in eighty-four years; so great is the difference between the births and burials. In some provinces of North America, if Dr. Franklin’s calculations are correct, the inhabitants doublethemselves in the short space of twenty-five, twenty-two, and even in fifteen years. On the other hand, in all the large cities of Europe: in Paris, Vienna, Rome, Dresden, Berlin, Amsterdam, London, Edinburgh, Dublin, and in almost all towns of considerable magnitude and population, the total annual births are inferior to the burials. It is calculated, that in London, within the last 150 years, near a million more of the human species have been wasted, beyond what were reared by its own original growth and procreation. But in small villages and country districts, the annual births exceed the burials; and it is from this redundance that a supply is furnished for the extraordinary consumption of armies, navies, war, colonization, emigration; exclusive of sickness, and other morbid casualties: the country and village surplus prevents depopulation.

Providence has also wisely ordained, that throughout those European kingdoms, of which we have any registers, a few more Males should be born than Females; andindeed such a surplus is rendered necessary from the waste by wars, emigration, intemperance, mechanical arts, and trades, the inclemency and vicissitudes of the weather and seasons, the vices and misfortunes to which political punishments are annexed; with various other noxious casualties, to all which the male sex are most exposed. In Dr. Arbuthnot’s Table, printed in theLondon Philosophical Transactions, of the proportion between the births of the sexes; in forty-six years were baptized of males, 329,742; of females, 308,644: excess of males only, 21,098. By the London bills, from 1657 to 1776, I find that there have been christened of males, 1,041,149; of females, 983,061, or as 18 to 17: and therefore, that in this long interval of 120 years, and comprehending two million of births, there is only a trifling excess of males, amounting to 58,088: a number which would scarce recruit the consumption of a few active campaigns. The excess of male beyond female births, is not so considerable as books of calculation have represented. In volume the 7th of thePhilosophical Transactionsabridged, there is an account of the annual births during several years at Vienna, Breslaw, Dresden, Leipsic, and Ratisbon: and in those cities, male and female births were as nineteen to eighteen. Amongst the abortives and stillborn, we also find the plurality of males. Lastly, if the registers can be depended upon, it appears that there are more births in Winter than in Summer, both in town and country. But although the fruit of the human womb may not have arrived at maturity before winter, it is no proof against the general law of the spring and summer influence on animals and vegetables, in contributing to fecundity and generation.

The Comparative Mortality of the Human Species, and of the Sexes at every Age, in City, Town, and Country; and in different Kingdoms of Europe: illustrated with a Chart, and with Tables. The Comparative Mortality of the Human Species, by different Diseases and Casualties: exhibiting a Chart, and Tables of all the Mortal Diseases and Casualties in London during Seventy-five Years: illustrated by and contrasted with the united Observations of Medical Authors, with various Hospital Registers; and with a Variety of Materials, Observations, and Comments of the Author.

Thatlearned Physician, Dr. Arbuthnot, in his Preface to Huygen’s “de Ratiociniis in ludo aleæ”, says, There are very few things which we know, which are not capable of being reduced to a mathematical reasoning; and when they cannot, it is a sign the knowledge of them isvery small and confused; and, when a mathematical reason can be had, it is as great a folly to make use of any other, as to grope for a thing in the dark when you have a candle standing by you. Medical writers, almost universally, have neglected, or barely skimmed the surface of the following important subjects. The public registers of births, burials, and diseases, are overlooked by all the modern systematick authors: they leave us equally ignorant of the aggregate, or comparative number, or force of those fiends which haunt and ravage the globe. To speak metaphorically, in medical books, the extensive desolation of the most rapacious tyrants and conquerors are confounded with the uninteresting history, and petty depredations of a robber. The detached observations of physicians, or other literary individuals, confined perhaps to a small town or parish, a meagre detail of village remarks, furnish, in innumerable instances, foundations too slight for the erection and stability of general proportions. In order to form useful tables of the ratio of mortality at various ages, to determine upon the absolute and relative havock by differentdiseases, upon the general effects of climate, season, local situation, diet, drink, luxuries, new customs, and manners, &c. we should extend our views far beyond the narrow bounds of a parish, or even of a province; we should include an interval of many years, collective numbers, and large groups of mankind.

It appears to me, that a great number of the fundamental principles, or of the primary orders of medical architecture, have not yet been established, neither in Pathology, to which this Dissertation is chiefly related; and much less in Therapeuticks. The lumber and mountain of ponderous systems, heaped together from Galen to Stahl, can only be compared to Egyptian pyramids. Except what has been done by a few authors, hereafter to be mentioned, the sciences of Medical Arithmetick and Universal Prognosticks, are new in medicine. In emergencies, the constant appeal has been, with oracular reverence, to aphorisms and opinions of individuals. In a word, no medical author has yet attempted to take the gages of life and death, and of morbid devastation, and, in one general survey, to encirclethe horizon of human existence and distempers. I have made some, at least laborious efforts, to rescue a momentous part of active medicine from that conjectural stigma with which the whole profession has been branded in the lump. And, however it may be slighted as an heretical innovation, I would strenuously recommend Medical Arithmetick, as a guide and compass through the labyrinth of Therapeuticks.

We are now to view the human race unexpectedly arrested, and struggling in the tragical and last stages of their terrestrial pilgrimage. The vision of human life is soon at an end: we are ushered into the world with lamentable exclamation; and are too often torn out of it in pain and agony. Bills of Mortality, however defective and inaccurate, yet sufficiently demonstrate this awful truth, that very few of the human species die of old age, or natural decay: by far the greater proportion are prematurely cut off by diseases. Of all the animal tribe, who usually bring forth one at a birth, none die in such numbers, in infancy, as the human race. In London, Vienna, Berlin, and every other overgrown metropolis of Europe, on an average, one half of the children born, die underthree years of age. But in country towns and villages, the proportion of infant mortality greatly abates. In some country towns of England, of considerable magnitude and population, as Manchester, half the children die under five; at Norwich, half under six; at Northampton, half under ten years of age. London, therefore, will have lost, out of equal capitals, a number in the intermediate space, between three and ten, more than Northampton.

Attend next to the small proportion of Infant Mortality in open country districts. By Dr. Short’s registers of several small country villages in England, the major part born live to 25, 27, 33, and 40. In many healthy country parishes, half the inhabitants born live to mature age; to 40, 46, and a few even to 50 and 60; and rear large families of children. In some extensive country districts of Switzerland, similar observations have been made by Susmilch and Muret. Here, therefore, is an astonishing disparity between the duration of city and country life: but particularly, let it be engraved upon the memory, in the early stages of puerile exigence. Infantsin cities resemble tender delicate plants excluded from fresh air; or fish confined in stagnant putrid water: they perish before acquiring a solidity and seasoning to endure the adulterated quality of the surrounding element; and their thread of life is then suspended by a tender cobweb.

Mortality, universally, during the first year after birth, is the most enormous in the funeral catalogue. A London infant at birth, has but an equal chance of living to three years old; whereas in the country, as before observed, half born survive to maturity. Upon reaching the third year, in cities, infants are somewhat seasoned, and the hurricane of puerile carnage is greatly abated. There is not afterwards such a prodigious disproportion between city and country mortality; and, in a few years after, from seven to ten, they approach nearer to an equality. From the London registers of burials, it appears that more die in the metropolis under two years of age, than from two to upwards of forty; and more under five years of age, than from five to between fifty and sixty: yet under five, there are but an inconsiderablenumber alive, compared to the latter class above that age: the deaths are greatly disproportioned to the living numbers or capitals. A few more die in the short interval between five and ten years of age, than in the succeeding double interval from ten to twenty. Between eight and sixteen years of age, one of every seventy of the Christ School boys is computed to die. Davenant rates the decrement in these years at only oneper cent.After reaching the tenth year, the torrent of mortality in city, town, and country, is subsided; and during the next eight or ten years of adolescence, very few die. From seven to ten, may be termed the highest pinnacle: having surmounted all the dangers and precipices of the early preceding journey, there is no stage wherein the future prospects of existence and longevity are so extensive. From birth to ten, the tide of life continues in annual gradation to increase; and from ten to the ultimate verge of existence, vitality continues gradually to ebb. Between twenty and thirty, more die in London than in the fifteen preceding years; and the burial list continues turgid to sixty; at which latter stage, the mortality is computed between four and fivepercent.

One reason, but not the only one, as I shall hereafter prove, of the great surge in the London bills, from twenty up to forty, is, that within this interval of life, the majority of the new settlers or recruits, arrive; and consequently augment the burials, from twenty to forty, beyond their natural proportion. After passing the meridian, and in the evening of life, the seasoned inhabitants of cities are said by Dr. Price, to have the advantage of the country, in health and longevity: that is to say, although the number who have survived in the country to sixty, seventy, and eighty, are greater proportionally than in cities, yet the latter class arrived at those years in London, have, comparatively, surer expectations of life. I do not, however, find this assertion verified in fact; the balance, if any, vibrating alternately on each side. The proportion of inhabitants who reach eighty years of age are computed, in London and Vienna, at one of every forty: but in country parishes, at one of every twenty-two; and in some, even one of every eleven. In both city and country, the few survivors at ninety, out of each thousand cœtaneous births, will have lost almost all theirfellow-travellers in the journey, long before reaching that goal; and about three or four only out of each thousand, on an average, will be then left alive.

There are a few instances of extraordinary Longevity, to 150 and 165; such are Jenkins and Par, in this island. In Bacon Lord Verulam’s History of Long Livers, male and female; their climate, diet, mode of life, appetites, exercises, studies, passions, dispositions, habits, and complexions, were exceedingly dissimilar. It is however probable, from observation and analogy, that the indigent and laborious class of mankind do not attain to longevity in the same proportion with the middling and more opulent ranks. The wandering Savages of America are notoriously short-lived. Throughout Europe, Asia, Africa, and America, the rich, the poor, the inhabitants of city and country, with very different complexion, climate, soil, diet, and conveniences, all seldom exceed the usual term of life allotted to man: seventy and eighty is mentioned in holy writ, as the brink of our earthly duration. Since the days of Moses; that is, between three and four thousandyears, human existence has been circumscribed within the same narrow bounds. In the London registers of mortality, during a period of thirty years, from 1728 to 1758, the total mortality is 750,332; and of all this number, 242 only reached beyond 100 years of age; one of whom arrived at 138. In some races and families of men, longevity seems to be hereditary; and his age, though little more than a dream, exceeds that of all other living creatures, a few only excepted. Amongst the quadruped creation, the elephant surpasses man in longevity: amongst the birds, the Swan, and a few others, have survived upwards of a century. The age of fishes is determined with more ingenuity than certainty: some seem to rival man in years. Among the numerous vegetable tribes, the Oak, Chestnut, and some other great trees, survive centuries.

On contrasting the mortality of Males and Females, it appears, that, notwithstanding the surplus of male births, the perils of childbearing, the many vexatious diseases peculiar to the fair sex, and that physicians and apothecaries have many more patients of the latter; yet the total aggregate number of livingfemales exceeds that of males, in most European kingdoms. Upon a numerical inquest in Edinburgh, and some other great cities, it was found, that females were to males as 4 to 3: in London, as 13 to 10; and in some other cities and towns, as 9 to 8. But in country districts, Graunt and Susmilch agree, that the two sexes approach nearer to an equality. In the province of Jersey, in North America, the males were found the majority. From 1702 to 1752; that is, during a period of fifty years, I find the proportion of male and female mortality in London as follows: Male deaths, 618,076; Female deaths, 626,692. Whence, therefore, does it happen, that female deaths preponderate over the male, when more of the latter are born, and, as calculators assert, the mortality of males, at all ages, is greater than that of females? As a solution of this difficulty and partial exception, I should suggest a greater exportation and transportation of males to the sea and land service, to nautical commerce, and to unhealthy climates.

Even in the Marriage State, the chance of survivorship seems considerably in favour ofthe wife. In Breslaw, during eight years, five married men died to three married women. Susmilch, on a scrutiny through several kingdoms and principalities of Germany, found, that three married men died to two married women. Dr. Price estimates the chance in favour of the wife being the survivor in marriage, as 3 to 2: and this calculation is confirmed by the experience of the general Clerical Society in Scotland, who have long established funds to support their widows. From their records, it appears that twenty married clergymen have died to twelve wives; or, as 5 to 3. By an accurate survey of several principalities and cities in Germany, and collected by Susmilch, the widows were to the widowers as 3, and even 4 to 1. At marriage, it should be observed, there is generally a disparity of age; the bridegroom is from six to twelve years older than the bride; and therefore should, in the course of nature, die sooner: and perhaps also more widowers, comparatively with the other sex, enter into a second marriage; which tends to reduce their numbers. Besides, husbands are more exposed to the vicissitudes of the weather and seasons, to excessive labour and noxious trades, and tomany other causes of diseases. Dr. Price finds, that the sexes respectively commence to be widowers and widows about 52 and 44; that is, men and women entering into matrimony, on a general average, at the age of 33 and 25, will become widowers and widows at 52 and 44: consequently, that each marriage will be dissolved by the death of one of them, in nineteen years; which is the ultimate term and probability of the husband and wife being both alive. For although some marriages may be protracted forty and fifty years, yet others may be dissolved in one year, or in a shorter time.

We have not yet sufficient information to determine the comparative chances of Female Longevity in the married and single state. At Berlin, indeed, calculators have remarked, that there were more married women alive at great ages, than of those who remained single. But such result might naturally be expected from a greater proportion in the decline of life of widows and wives, compared to antiquated virgins. From the ages of fifteen to twenty-five, married women likewise are said to have the advantageof the single, in whom the dictates of nature are frustrated and violated.

Comparing the mortality of the Seasons, Dr. Short found, from a variety of country-registers, that mortality generally begins its reign in December; that at March it is in its zenith; and at May in its declension. In twenty-five country towns and parishes, he found the winter to the summer mortality as 50 to 41. At Manchester, a country town of England, Dr. Percival found the winter to the summer mortality as 11 to 8. At Vevey, in Switzerland, during sixty years, Mr. Muret found the burials, during the four winter months, as 5 to 4 to those of the summer. Another proof of this is recorded in theRecherches sur la Population, par Messance: The total sick admitted into theHotel Dieuhospital in Paris, from 1724 to 1763 (forty years) were, in the four winter months, December, January, February, and March, 314,824; and in the four summer months, June, July, August, September, 238,522; or as 4 to 3. In London too, the undertaker’s, harvest is in winter. There is one obvious reason why, in every metropolis, thewinter mortality should exceed that of summer, from the greater concourse of inhabitants of all ranks: but, independent of additional population in winter, the same law seems to prevail in country places. In a subsequent part I shall attempt to throw some collateral illustration upon the subject.

Let us close this humiliating scene with a general abstract of human carnage. If we scan the dolorous mansions of disease, we find, on an average, 1 death, annually, out of every 5 families in cities: but in country towns, and open districts, 1 of 7, 8, 9; and in a few healthy places, 1 of every 10 families. Including the whole assemblage of inhabitants in city, town, and country, from birth to the extreme of existence, they are computed to die in the following annual proportion to the living: In London, 1 of 21; Dublin, 1 of 22; Edinburgh, 1 of 21; Vienna, 1 of 20; Amsterdam, 1 of 22; Berlin, 1 of 26. This is nearly Dr. Price’s calculation; but Halley and Susmilch compute only 1 of 22 to 29 to die annually in cities. In smaller cities and towns, such as Norwich and Northampton, the generalaverage of deaths is 1 of 24 to 26; but in several provinces and healthy country villages, 1 of 32 and 33, up to 45, 50, and even 60, is the annual drain: 1 of 43 to 50 was the average in upwards of a thousand country parishes on the continent; and recorded in Susmilch. Within the above short intervals of time, there will have died in the respective cities and country places enumerated, a number equal to the whole inhabitants. But the annual decrease of the oppressed Negroes, in the West India islands, is estimated at 1 of 7.

The ancient Egyptians allotted 3 generations to a century, which is bordering upon the truth; at this day, 1 of 32 and 33 up to 35, is near the measure of a generation, and to the general decrease of a community throughout Europe, comprehending all the inhabitants in city, village, and country: that is, mankind share amongst them from about 32 and 33 to 35 years each of existence: and within this fugitive interval of time, a number equal to all the present inhabitants of this island, or of the whole earth, will be exterminated. If we extend this estimateto the whole human race, eight hundred million will die in 33 years; about twenty-eight million annually; seventy or eighty thousand daily; about three thousand hourly; and from fifty to sixty every minute. It is perhaps superfluous to add, that, in the same intervals, an equal or superior number will be born.

According to De Moivre and Dr. Price, “the probabilities or expectation of life, decrease as we advance from childhood to old age, in an arithmetical progression; that is, in such a manner that the difference is always the same between the number of persons living at the beginning of any one year, and the number living at the beginning of the following year.” Or, in other words, less enveloped in mathematical obscurity, out of any specified number, an hundred or a thousand, the same proportion will continue to die every year until near 80 years of age and upwards: consequently, the probabilities of life are constantly decreasing; because notwithstanding the progressive annual drain from the capitals, yet the deaths continuethroughout equal. But this proportion is certainly erroneous in the first stages of life, and until about 10. View the above proposition in another light.

From any given number there will be an equal drain annually, until what De Moivre terms thecomplementormaximum, or utmost probable extreme of life, which he fixes at 86, all are dead. The probability, therefore, that the whole of any limited number whatsoever, or age, will all be exterminated is the number of years between 86 and the year such a number are all alive. Of 56 persons alive at 30, they should all be dead in 56 years, because 56 added to 30 amounts to 86, the maximum: of 46 persons alive at 40 years of age, they should all be dead in 46 years: and 36 persons alive at 50 years of age, should be dead in 36 years; for 50 and 36 complete the maximum. Again, the expectation of any single life is only half the maximum or complement, or half the space between that age and the ultimate term of existence: but here we must repeat the former exception, and draw the line after 10years of age. The expectation of two equal joint lives, according to De Moivre, is one third of the complement of life. Example: two lives, aged 40, have an even chance or probable prospect of continuing together in exigence only 15 years; which is the third of the complement, reckoning from 40 to 86: the expectation of the survivor is also 15. Or, suppose a lot of marriages of persons at 40 years of age, they will, on an average, continue together 15½ years; and the survivors the same time after. This expectation, therefore, is the probable duration of each marriage, and the share of each person’s life. But it may be proper to add, that the duration of marriages, and the value of single and joint lives, will, on a promiscuous calculation, be different from the registers of annuitant and insurance offices; because they are scrupulously vigilant to exclude all diseased and unhealthy persons from becoming members.

The following Chart and Tables, present a distinct prospect of the fates clipping the mortal thread, from birth to old age, incity and country. But we are not to suppose that in every instance there will be annually a regular arithmetical diminution, as marked in the different tables: some years will be more fatal than others; and we are to form estimates from an average of several years. The first column points out the age, the second the number living at that age, the third the number who die during the year; and so on to the end of the table. But observe, that the number of infants, at the beginning of the second column, are supposed to be all born together on the first day of that year; and this rule applies throughout all the remaining ages. The two short tables of 15 and 30 years mortality in London, demonstrate the gradations at longer intervals than a single year. From these different tables may be estimated the annual waste, out of any specified number, at all ages, the ultimate prospects of existence, and the odds or probability of a person in health surviving a stated number of years.

Shewing the Probability of the Duration of Life inLondon, deduced by Mr. Simpson, from Observations on the Bills of Mortality in London for Ten Years, from 1728 to 1737. The total Number of Inhabitants, probably, about 650,000 in Winter. One Half born died under Three Years of Age.

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