Popular Science Monthly/Volume 10/April 1877/Vital Statistics
NO subject of scientific research has within the present century received more earnest attention from thoughtful minds than that of statistics. None, moreover, is more worthy of investigation or fruitful of more satisfactory practical results to humanity. It must be confessed that careless or dishonest observers occasionally misconstrue or misinterpret the significance of statistics; but the same is equally the case with all facts. There can be no doubt that certain truths are demonstrable by figures, and that we must accept almost without qualification the old adage that "figures cannot lie." We should not confound with statistics themselves the erroneous deductions drawn from them so frequently.
Among the various divisions of statistics the one which relates more particularly to birth, marriage, and death, must always occupy the most prominent place in human interest. It is this to which the expression vital statistics has appropriately been applied, and as "self-preservation is the first law of Nature," so if by a study of this science we can, so to speak, grapple with Death himself and retard his course even for a time, we may assuredly congratulate mankind. This science, as its name implies, takes cognizance of the essential circumstances of human existence, while it must obviously possess inherent and intimate relations with other branches of statistical inquiry, viz., those of morals, industrial pursuits, customs and modes of life, material prosperity, peculiarities of soil and climate, domestic economy, and even political tendencies and events.
If the deductions gained from vital statistics are to be of value in the preservation of life, those facts which bear particularly upon the preventable causes of death must naturally claim our more immediate consideration. The subject of mortuary statistics is, indeed, one of profound interest. All civilized nations have finally recognized its importance, and have by more or less stringent legislative enactments enforced the collection, preservation, and proper arrangement and analysis, of those data which constitute its foundation. It must be acknowledged that even exact figures of mortality do not always indicate with positive accuracy prevailing conditions of the public health, especially in the case of affections subject to constant fluctuations of type. They are, however, indices which point unerringly in the right direction, and, as such, they are entitled to our most careful consideration. Moreover, they are our sole means at present for approximate investigation of national disease. We may trust that ere long the concerted action of the entire medical profession will furnish us with a constant knowledge of the comparative prevalence of all disease. In the United States the want of such a system is in a manner compensated for by the periodical enumeration of causes of death at each national census. Although for obvious reasons such enumeration must be defective, both as regards the actual causes themselves and the number dying within the census year (the returns of 1870 being computed as forty-one per cent. less than the true number), still, the same sources of error and the same elements of truth obtaining, as a rule, in every section, the results of comparisons between different portions of the country contain much less of fallacy and more of fact than might be anticipated. For the last census year, ending June 1, 1870, nearly half a million deaths were collated and appropriately arranged by the Census Bureau, in tables referring both to the country as a whole and to separate States and Territories.
Among our English kinsmen across the Atlantic there has existed for many years a uniform and comprehensive system of death-registration. Thus, within a brief period of the outbreak after an epidemic, its mortuary figures from every quarter reach the central bureau in London, where they are at once systematically tabulated and published. The character of the morbific storm is studied, and its course predicted with almost as much certainty and promptness as each approaching disturbance of the elements is foretold and described in Washington from a comparison of manifold meteorological phenomena. In the same manner, whatever peculiarities may characterize the mortality by sporadic and endemic affections at different seasons, in various portions of the country, are observed and converted into numerical expressions for analytical study.
It is unfortunate for the cause of medical and sanitary science that no similar system has yet been established in this country. In our population of forty-odd millions over seven hundred thousand deaths must have occurred within the last twelve months; and yet, except in the case of our large cities, we are almost as ignorant of our causes of mortality as we are of those which cut off the population of China.
The British system, one applicable to the peculiarities of different populations, was devised by Dr. William Farr, the distinguished medical director of the English Registrar-General's office. A statistical congress, under the auspices of the French Government, was convened in Paris in September, 1855, to consider this subject, and it agreed upon a nomenclature of the causes of death substantially the same as that proposed by Dr. Farr. At another congress held in Vienna, in 1857, a uniform nomenclature and plan of registration for all the European states was determined upon. Dr. Farr's classification of diseases was not so generally adopted; but it has since been making its way in Germany and other portions of Europe. This nosological classification, though by no means perfect, doubtless possesses, in its practical relations to public health, advantages over every system that has preceded it. Its divisions are founded upon the manner in which diseases of similar type or character affect the population. It will be sufficient to mention its first great class—that of zymotic diseases. This term zymotic is derived from a Greek word meaning ferment, and has reference to a change analogous to that of fermentation occurring in the blood by the infinite multiplication of disease-germs. Such affections chiefly comprise fevers par excellence—the epidemic, endemic, and contagious or infectious disorders—which suddenly attack masses of people, which spring from different sorts of malaria, or from specific communicable poisons; contaminate the atmosphere and water, and decimate in a brief time civil and military communities. We read in sacred history of whole armies having been suddenly swept away, as that of Sennacherib, which, while besieging Jerusalem, lost 185,000 men in a single night under the deadly breath of the destroying angel—a beautiful metaphor, probably, for the swift and invisible blow of the pestilence. It has been well remarked that these diseases distinguish one country from another, one year from another. They have formed epochs in chronology, and, as Niebuhr has shown, "have influenced not only the fall of cities, such as Athens and Florence, but of empires."
This great class of maladies is the index of salubrity; it is this class which varies to the greatest extent in different climates and seasons, which modifies the fatality of other kinds of disease, and which constitutes the principal difference between the health of different peoples and periods.
A general and uniform system of death-registration among nations renders easy what would otherwise be impracticable, viz., constant international exchanges and comparisons, not simply confined to individual affections, but applicable as well to immense groups of cognate diseases. In this manner statistics of mortality assume vast importance, and present for our consideration manifold questions of a physical, social, and political character. They determine the laws which regulate the duration of life; they indicate in what manner those laws have been or are being infringed, and afford bases for calculations materially affecting the interests of mankind. Statistics are far from being the barren array of figures ingeniously and laboriously combined into columns and tables, which some persons are apt to consider them. They constitute rather the ledger of the people, in which, as the merchant in his books, the citizen can read at once all the results of a week, a month, a year, or series of years, and can deduce the profit or the loss which has accrued to the account of vitality, morals, education, wealth, power. And it has been well said that "science has nothing to offer more inviting in speculation than the laws of vitality, the variations of those laws in the two sexes at different ages, and the influence of civilization, occupation, locality, seasons, and other physical agencies, either in generating diseases or in improving the public health."
But, putting aside this broad and philosophic view of the importance of mortuary statistics, it is evident that the application of their deductions must be of great benefit to the physician as a practitioner alone. This was perceived even as far back as the time of Sydenham, who inculcated the doctrine that the treatment of all disease should have a reference not only to the immediate symptoms and to the season, but also to the epidemic constitution of the year and the locality. It has been remarked by a distinguished author that "man is not born, does not live, does not suffer, does not die, in the same manner on all points of the earth. Birth, life, disease, and death, all change with the climate and soil—all are modified by race and nationality." Medicine, with the other natural sciences, has now been obliged to abandon vague hypotheses for truths determined by observation. Numerical expressions are substituted for uncertain and conjectural assertions. Only a limited number of facts are, however, contained within the horizon of a few observers. The determination of the laws of mortality requires a very wide range of observation, and a considerable space of time, in order to eliminate accidental perturbations.
The next important element of vital statistics is that of birth. Man is ushered into existence under natural circumstances almost as impressive as those which circumscribe his duration of life, and which attend its surrender. While tens of thousands are divesting their being of earthly garb, and entering upon their eternal inheritance, still greater numbers are assuming the heritage of life in forms moulded by antecedent events, and stamped with ancestral peculiarities. If, therefore, it be profoundly interesting to contemplate, arrange, and study the multitude of agencies which impel this innumerable caravan of pilgrims toward their destination, it is almost equally instructive to analyze the manifold causes which have contributed to their assembling together. Such particulars, when massed into statistics, become of acknowledged importance to medical and social science. The disparity in the sexes born at different periods, the average number of women bearing twins, triplets, etc., the proportion of offspring from native or foreign progenitors, the ages and occupations of parents, the average number of children produced at different periods of female life and in different seasons, the influence upon reproduction of the relative ages of parents, the reciprocal relations between illegitimacy and modes of living—these and other kindred questions are of deep concern to the human race, and the source of their solution lies in the largest accumulation of facts.
Moreover, the actual number of births occurring in any community each year is indispensable, in conjunction with other factors, for computing the increment of population during years intervening between those of official enumerations, and consequently for the determination of the true death-rate. The remarkable precision with which this increase may be approximated is exhibited by the London tables, according to which the estimated population of that city on April 2, 1871, was 3,247,631; while the decennial census completed on the same night gave the number of the inhabitants as 3,251,804—a difference of only about four thousand in three and a quarter millions—one almost inappreciable in the calculation of percentages.
To the casual thinker, statistics of marriage might seem of little consequence. But, in fact, the deductions from a review of marriage-returns are of positive value not only to the moral philosopher, but to the political economist as well. The relations of marriage to various industries—to mining, agriculture, trade, commerce—in a word, to the material prosperity of a people—have been well established by statistics. A decided diminution in the marriage-rate of a community within a given period of time is an unerring indication that war or pestilence, or commercial crisis, or other great disturbing force, has rendered the necessaries of life clear, and occupation difficult to procure. The various forms of marriage—the numbers of bachelors, widowers, spinsters, and widows, united in wedlock; the tendency to early or late marriages among certain classes and peoples; the condition of elementary education as indicated by the proportion of men and women capable of signing their names to marriage-documents; the effect of a demand for skilled labor upon the proportion of early marriages; the relations between waste of life and proportions of marriages and births in towns as contrasted with rural districts; the influence of the marriage-rate on morality; the ratio of marriages to births, and its conformity to density and character of population, and to industrial pursuits—all of these considerations furnish assuredly social problems of deep and constantly increasing importance to civilization.