Scotland 1885-90 120 England Belgium France Holland Italy 1884-91 192 Density of Population.- Density has a decided effect upon the general death-rate; other things being equal, the greater the density, the higher the death-rate. Dr. Farr found that the death-rate varied, not in direct proportion, but in proportion to the sixth root of the different densities. When applied to English, and American urban populations at the present day, however, this rule does not hold good. In English cities, during the past 50 years the death-rate appears to have gradually diminished, while the density has increased, thus showing that counteracting sanitary influences have had an appreciable effect. Newsholme states that the true density is the number of persons to each room, not the number on a given area. Effect of Occupation.-The mean age at death is not a trustworthy index of the effect of occupations upon health. For example, if a large number of employees in some industry is thrown out of employment by a strike or lockout, and their places are filled by younger persons at lower wages, it is plain that the mean age at death of the latter group will be less than that of the former group, independently of sanitary conditions. So the mean age at death of judges is greater than that of law students, since judges are not usually appointed until after middle life. The only trust worthy method is to compare the mortality of those engaged in one occupation, and of a given age with the mortality of those engaged in other occupations, and of corresponding ages. The adoption of a "comparative mortality figure" renders the comparison more intelligible. This method is adopted by the registrar-general of England in the Supplement to his 55th Annual Report, from which the following figures are taken. These are for the years 1890-92, and are based upon the four age groups 25-35, 35-45, 45-55, 55-65 years. COMPARATIVE MORTALITY FIGURES OF MALES FROM 25 TO 65 YEARS OF AGE, ENGAGED IN Slaters 1,322 Steel grinders.....1,412 Brewers ...... 1,427 The foregoing table should be read as follows: The same number of men aged 25-65 that would give 1,000 deaths among all males, would give 533 among the clergy, 563 among farmers, 843 among lawyers, 966 among physicians, 1,659 among innkeepers, and 1,810 among file makers. The comparatively high mortality among the unoccupied is doubtless due to the fact that the bulk of this class consists of those who are physically feeble and unfit for employment of any kind, and as fast as these are eliminated by a high death-rate, their places are filled by recruits from the ranks of the employed class. Examining the figures more specifically with regard to the diseases to which persons employed in certain occupations are liable,-cancer apPears to cause a high mortality among chimney sweeps; diseases of the nervous system among brewers, innkeepers, file makers, and lead workers, bronchitis among steel grinders, glass-blowers, manufacturing chemists and potters; lead poisoning among potters, file makers, and leadworkers, accidents among railway employees, coal miners, and seamen. The effects of breathing dust laden air are manifest among quarrymen, copper and zinc workers, file makers, tin miners, cutlers and scissors grinders, potters and earthenware makers, in the mortality from phthisis; of alcoholic excess from the different diseases which attack the viscera of the body, the highest mortality from these causes (diseases of the liver, nervous system, the urinary organs and gout) being found among brewers, inn servants, effects of alcoholic excess. and innkeepers who are most exposed to the evil The Causes of Death.-The causes of death are usually stated either as a ratio of the mortality from all causes, or as a definite proportion of the living population. The latter is the better method when the number of the population and of each specific cause is known with a the mortality in England and in Massachusetts fair degree of accuracy. In the following table from certain diseases is presented for the year 1900 by both methods. chusetts are for the cities and towns having over The figures for Massa5.000 in each, which comprise four fifths of the entire population. DEATH RATES FROM CERTAIN CAUSES IN ENGLAND AND MASSACHUSETTS, 1900. 727 Whooping cough architects... 778 Typhoid fever.. Bronchitis 16.9 783 Pneumonia 533 Lawyers 821 7.1 Fishermen 845 dysentery 966 989 Influenza 604 Woolen mill opera 27.6 12.4 Smallpox 664 tives 996 ......1,000 selected healthy districts... 679 Occupied males..... 953 Unoccupied males..2,215 Clergymen Gardeners and nur ... Agricultural laborers 666 і on. VITAL STATISTICS Life tables-Life-tables offer an accurate means of measuring the probabilities of life and death. They represent "a generation of individuals passing through time." The data which are required for the construction of a lifetable are the number and ages of the living, and the number and ages of the dying. (1) Theoretically, the best plan for forming a life-table would be to observe a definite number of children, say 100,000 or 1,000,000, all born at the same time, throughout life, entering in a column the number who remain alive at the end of each successive year until all are dead. In a second column the number dying before the completion of each year of life is also entered opposite the corresponding age in the first column. The number who die under one year of age is placed in the column opposite the age o and so This method being impracticable, it becomes necessary to resort to other and shorter methods. (2) If any large number of children could be traced through life, however various the dates of their birth, a life-table could be constructed from the data thus observed, if the numbers of the living and dying in each year of life are known. (3) The mortality experience of a single year may be exceptional, hence it is customary to take the experience of a series of years, five or ten, for example, as is usually done in constructing the English life-tables. The numbers of children of each sex at birth are not equal, hence it is customary to start with the proportionate number of each sex actually born. For example, in a city of 1,000,000 inhabitants in the 10 years 1890-1900 there were 300,000 living births or 30 per 1,000 annually, but the numbers of each sex were 152,460 males and 147,540 females, or in the ratio of 50,820 males and 49,180 females, these two combined making 100,000. Dr. Newsholme describes the method of construction of his life-table as follows, in his second Brighton life-table published at Brighton, England, in 1903: Knowing the number living and dying in each year of life the probability of living one year is represented for each year of life except the first by the fraction number of survivors at end of year. number of living at beginning of year. The deaths in the first year are very unequally distributed. Out of 3,036 male deaths under one year of age in Brighton in 1891-1900, 2,142 occurred in the first and 894 in the second half year. The probability for the first year of life is obtained by dividing the mean population minus the deaths in the second six months of life, by the mean population plus the deaths in the first six months. Thus for males: infants living at the end of a year is obtained by multiplying 50,614 by the probability of living to the end of the first year. 50,614 X.83194= 42,108 and for the second year 42,108X.95213 40,092 and so on. The probability of living one year is the best method of stating the immediate prospects of life. The number surviving at any given age is determined by the probabilities of living a year during all preceding ages. To ascertain the future prospects of life for each sex (mean expectation of life) we must find the total number of years lived by the 50,614 male, and 49,386 female children, and divide this sum by the number living this total number of years. The 42,108 male children surviving at the end of the first year of life out of 50,614 born are reduced by death to 40,092 at the end of the second year. After the first year, the deaths may be assumed to be evenly distributed throughout the year and hence the number of survivors at the middle of the second year, or the average number of persons alive between 42,108 and 40,092 or 41,100. This numduring the year, may be considered as the mean ber is termed P. It is evident that the number of years of life lived between ages 1 and 2 by the 42,108 males entering the second year of life must equal the average number living during the year or 41,100. So during the third year the 40,092 males entering the year live 39,660 years and so on. Hence the 50,614 born live a total of 45,196 + 41,100 + 39,660 + 38,967 + 11+6+2+1=2,272,668 years until the last survivor dies. This total, termed Q. and Q1, is similarly the total number of years lived by the 42,108 males surviving at age I and so on. The average life-time of each male born is thus 2,272,668 Qo E; and generally Ex or 50,614 the average future life-time or expectation of Qx life at any age x= 1x BRIGHTON AGE or lo LIFE-TABLE. MALES. (CONDENSED.) Based on the mortality of the years 1891-1900. 012345: .83194 50,614 45.196 .98670 .95213 42,108 41.100 2.227.472 52.90 .97843 40.092 39.660 2.186.372 54.53 38.967 2.146.712 54-75 38.533 2.107.745 54.46 38.271 2.069.212 53.94 39.228 38.706 .99536 38.360 .99108 99 A life-table similarly constructed for Massachusetts upon the mortality of the five years 1893-7 gave the following results for the first years of life: VITAL STATISTICS PopulaYears of Expecta tion or years of life lived life lived in and in each year of age above each year of age I 8,849 I,794 818 559 51,350 46,343 2,263,907 42,501 41,604 2,217,564 40,707 40,298 2,175,960 4 424 39,889 39,330 5 0423 + tion of life at each year of age Ex 44.09 52.18 53.48 39,609 2,135,662 53.54 39,118 2,096,053 53.29 316 38,906 38,748 2,056,935 52.87 The foregoing analytical method requires much calculation and interpolation of figures at the intervening years between ages 10, 20, 30, etc. A convenient and fairly accurate method of constructing a life table is the graphic method described by Newsholme, in which the data are represented for the population and deaths upon sheets of cross section paper. Upon the population sheet the numbers living at each age group are represented by parallelograms, in which the heights of the ordinates from the base line represent the numbers living for each year of life. Upon the other sheet the deaths are shown in like manner. The lines representing the population and the deaths are drawn by connecting the middle points at the tops of the parallelograms. The conditions which affect the accuracy of life-tables are chiefly the effect of migration, the defects of the census, the practice of incorrectly reporting the ages of the living and the dead, and defects in the registration of births and deaths. To remedy these defects, especially in instances where life-tables are constructed from the data of small towns or groups of population, the system of interpolation already referred to becomes necessary for the correction of inaccuracies. that is, the possibility of error = 0.0623 of unity or 6.23 per cent. In other words, in a second series of cases of diphtheria under the same conditions as the foregoing, the fatality may vary from 4.77 to 17.23 per cent, an indefinite result which indicates that the first series cannot be depended upon as establishing more than a prima facie case in favor of any special treatment that may have been adopted. If 20,000 cases and 2,200 deaths had been obparatively small. An illustration of this point may be found in the Medical and Surgical History of the War of the Rebellion,' where it is stated that the observed fatality of sabre wounds penetrating the abdominal cavity without injuring the viscera was 100 per cent, while the fatality of sabre wounds penetrating the pelvis was o per cent. But the actual number involved in each case was only one. As they stand these observed facts have absolutely no value. Had the number of observed facts been 100 or 1,000 these percentages would undoubtedly have been very much modified. The steady decrease in the limits of possible error as the number of recorded facts increases is shown in the following table, where, in the first line there are 7 recoveries (70 per cent) out of 10 cases, and in the last line 700,000 out of 1,000,000 cases. In the first instance the fallacy of drawing conclusions from a small number of cases is shown, since the possible recoveries are actually greater than the whole number of cases. served the limits of error would have been com Total number Number of of cases recoveries ΤΟ 100 1,000 10,000 100,000 1,000,000 7 70 57,000 or 73,000 700 66,000 or 74,000 7,000 70,000 700,000 68,700 or 71,300 Errors from Incomparability of Data.- The data to be compared should be strictly comparable. The conclusion that a certain remedy or method is valuable in the treatment of cer tain diseases is not demonstrated by the fact that the fatality in a series of cases treated with this remedy is 5 per cent while in another series of cases treated without it, the fatality is 20 per cent, unless it is shown that the ages, and other previous conditions of the patients in the two cases are not widely different, and unless the numbers constituting the series are sufficiently great to avoid the fallacy due to pau The larger the number of the total observations city of data. 2 m n (a) the less will be the value of 2 a3 Errors from the Composition of Rates.— These are very common and show the fallacy of dealing with average rates by any method and the less will be the limits of error in the different from that of dealing with the sums of m simple proportion a the numbers compared. For example, a certain county is made up of four municipalities, a, b, c, and d. The death rate of a in 1900 was 20.81, Maine 682,655 PRINCIPAL VITAL STATISTICS OF THE SIX NEW ENGLAND STATES (FOR THE IO YEARS 1892-1901). The figures under the name of each State are the estimated mean annual populations of these States for the 10 year period. In the foregoing table for the sake of greater accuracy, the deaths under one year are compared with the registered births, not with the population. INTERNATIONAL VITAL STATISTICS. (Births and deaths per 1,000 living, in European countries, in the 25 years 1876-1900, and in the year 1901.) VITAL STATISTICS England Wales and Scotland Ireland Denmark Norway Sweden Austria Hungary Switzer- German Holland Belgium France Spain Italy land Empire VITASCOPE - VITEBSK that of b was 19.02, that of c. 14.14, and that of d 7.59. If these are averaged as follows: the resulting death- 20.81 19.02 14.14 7.59 4)61.56 15.39 Population MUNICIPALITIES Therefore, 10,395 611,417 12,512 X 1000 Deaths in 1900 11,671 12,512 making the enormous death-rate of 123 per 1,000 (2) The death-rate from the principal infectious diseases is often quoted as an index of sanitary conditions. In consequence of the different methods by which such diseases are spread, the modes of prevention also differ, and are more easily applied in some diseases than they are in others. For example, a high deathrate from typhoid fever in a city or a town would indicate a greater neglect of sanitary precautions than a high death-rate from influenza. (3) Infant mortality constitutes a delicate test of sanitary conditions, but should not be quoted as the only test. It should always be =20.46 per 1000, stated as a proportion of the births, and not as a proportion of the persons living under one year according to the census, since the latter is exceedingly liable to error. 611,417 the true death-rate of the county. The error in the first instance arises from the fact that the larger city, with over 93 per cent of the total population, and the small town, with less than I per cent, are each given equal prominence in obtaining the result. Errors from Stating Deaths as a Ratio of the Total Mortality.— There is nothing erroneous per se in stating the deaths from any special cause, or at any age, as a percentage of the total mortality from all causes or at all ages. It is a useful, and, in fact, the only method practicable when it becomes necessary to state the proportion of one of them to the other. But beyond this the method is untrustworthy. For example, the proportion of fatal accidents in Massachusetts in 1900 among boys under five years of age was 14.5 per cent of all fatal accidents among males, and that of girls of the same age was 24.3 per cent of all fatal accidents of females. From these figures, however, it cannot be inferred that girls are more liable to fatal accidents than boys, since the contrary is the fact, the actual numbers being 205 such deaths among boys under five, and 126 among girls of the same age. The only reasonable conclusion is that at higher ages females are much less subject to fatal accidents than males. When stated as a ratio of the living population of the same ages, the deaths by accidents of boys under five were 14 per 10,000, and those of girls of the same age were only 9 per 10,000. Vital Statistics as Tests of Sanitary Conditions.-(1) The most commonly applied test for determining the comparative healthfulness of different communities is the general deathrate. This test, however, has certain limitations. It may be trusted for comparing the health of a city, town, or district for any given year with that of the same community for a preceding year or period. But if employed for comparison with the death-rates of other places there is great liability to error. (a.) Because of differences in the age and sex constitution of the places compared with each other. The error may be corrected by referring the figures of each place to a common standard. (b.) Correction should be made for deaths in pub lic and private institutions of persons other than residents. For example, in a small town in 1900 having a population of 3,683, the deaths were 453, (4.) A more exact method is to construct a life-table, by which the expectation of life may be compared in different districts, as well as among the different classes of the population. Life-tables published in England for different districts and different classes of people show marked differences, according to the varying conditions in which such classes of the population are living. ures In the two tables herewith the following figare presented: (1) The principal vital statistics of the New England States for the 10 years, 1892-1901. (2) The births and deathrates of fifteen European countries. 'Elements Bibliography.- Newsholme, of Vital Statistics' (1899); Farr, English Life Table (1864); Longstaff, 'Studies in Statistics (1891); Annual Reports of the Registrar-Generals of England, Scotland and Ireland; Rumsey, 'Some Fallacies of Statistics' (1875); United States Census Reports of Mortality (1880, 1890, and 1900); Registration Reports of and New Jersey; Bulletin de l'Institut InternaNew England States, Michigan, New York, tional de Statistique; Statistica delle cause di Rome (1901); Böckh, Statistisches Jahrbuch der Stadt Berlin) (1880-1902); Körösi, Statistisches Jahrbuch der Stadt Budapesth' (1900); Billings, The Cartwright Lectures▸ (1889). SAMUEL W. ABBOTT, morte State Board of Health, Boston, Mass. Vi'tascope. See BIOGRAPH. Vitebsk, vē-těbsk', West Russia, (1) the capital of a province of the same name, on both sides of the Duna, 791⁄2 miles by rail northwest of Smolensk. It has more than 30 churches, including six Roman Catholic, two synagogues, an old palace, a theatre, a gymnasium, and a hospital, manufactures of mead and leather, and an active transit trade. Pop. about 70,000. (2) A western province surrounded by Pskov, Smolensk, Mohilev, Minsk, Vilna, Courland, and Livonia; area, 17,440 square miles. The surface is in general hilly; in the depressions are numerous marshes and more than 2,500 lakes, of which the largest are Lubahan, Rasno, Nevel, Sebesh, and Osvea. The chief rivers are the |