Part 37

The Carlisle table is taken as the standard for the duration of life, to measure the loss of life in the several districts, as it gives the probability of life from infancy, well ascertained for one town, and nearly coincides with the experience of the annuity offices on the select class of lives insured by them, and with the results which I have obtained from the mortuary registries showing the average age of death in the county of Hereford. Each of the recognized insurance tables may, however, be used. If the Carlisle table be taken, the chances of life at infancy would be 38·72; by the Chester table it would be 36·70; by the Northampton, 25·18; by the Montpellier table, 25·36; by the last Swedish table, 39·39; by the experience of Geneva, 40·18. After the attainment of twenty years of age these several tables give the chances of life as follows:—by the Carlisle table it would be 41·46; by the Chester table, 36·48; by the Northampton table, 33·43; by the Montpellier table, 37·99; by the Swedish table, 39·98; by the Geneva experience, 37·67; and by the experience of the Equitable Society, 41·67. For civic purposes in this country, the most important period for considering the chances of life is after coming of age, or after the attainment of twenty-one years; the average ages of all who die above that age in each district of the metropolis are therefore given to illustrate the extent of loss of life to each class of adults, which is the more important to be observed, as it has been hastily supposed that the pressure of the more common and removable causes of disease is almost exclusively upon the infant population.

In illustration of the errors occasioned by taking the proportions of deaths as the exponent of the duration of life; if we take the proportions of deaths in the district of Islington, with its population of 55,720, we find the deaths for the year only 1 to every 55 of the population, which would appear to be a highly healthy standard; whereas, when we examine the average age of death of all of that population who have died during that year, we find it to be only 29 years: in other words, we find that the average duration of the period of existence has even in that district been shortened by at least nine years to all, and to an extent of at least six years on the average to the class of adults. If we examine the pressure of the causes of death upon each class of the community, in the same district, we find that the class of artisans, instead of attaining 39 _years_, have, on the average, been cut off at 19 years; and hence that children and adults, and on the average all those of the labouring classes who have died, have been deprived of 20 years of the natural expectation of life; and that even the class of adults who have died have been deprived of 15 years of working ability, involving extensive orphanage and premature widowhood. If we take such a district as Bethnal Green, inhabited by weavers and a badly conditioned population, the returns of the proportionate number of deaths to the population (1 in 41) would lead to the supposition of an average vitality of nearly double the real amount, which appears from this year’s return to be only 22 years for the whole population. For the working classes in that district it is no more than 18 years. If we carry investigations closer, and into the local causes of the mortality, we have them developed in such evidence as that given by Mr. T. Taylor, one of the registrars of that district;—or in other districts by such information as that given by Mr. Worrell, the registrar of St. Pancras, or by registrars of St. George’s, Hanover Square, or by the registrar of a district of Marylebone, where we find the state of overcrowding (noted in § 26), combined with the insufficient supplies of water, the defective drainage and neglect of cleansing which is described in the answers—attended by a reduction of 12 years’ duration of life to the adult artisans. In the opulent parish of St. George’s, Hanover Square, it is attended by a loss of 16 years; in Marylebone and in St. Pancras, by a loss of 17 years. The external and internal circumstances of the labouring population, where such results have been obtained, vary widely, and the results are commonly the mean of extreme differences. For example, in the parish of St. Margaret’s, Leicester, which has a population of 22,000, almost all of whom are artisans engaged in the manufacture of stockings, where the average age of death in the whole parish was, during the year 1840, 18 years, I succeeded in obtaining the ages of death in the different _streets_, when it appeared that this average was made up as follows:—Average age of deaths in the streets that were drained (and that by no means perfectly) 23½ years; in the streets that were partially drained, 17½ years; in the streets that were entirely undrained, 13½ years. Though the defective drainage and cleansing was the main cause, it was doubtless not the only cause of this variation. That, however, was a year of a heavy mortality, and the average age of death in that and another district during the years 1840, 1841, and 1842, was in the streets drained 25½ years; in those partly drained 21, and those not drained, 17 years. The general average was 21 years. The proportions of death to the population in Leicester were during the same period, 1 in 36½. The inquiries promoted in the districts of other towns have developed instances of large masses of population amongst whom even lower average duration of life than any noted in the first report is attendant on the circumstances described as causes.

So far as estimates of the number of the people before a census was taken may be depended upon, it appears that the proportionate numbers of deaths in the metropolis were, at the commencement of the last century, 1 to 20. At the time the first census was taken (1801) the proportion of deaths to the population within the bills of mortality appeared to be 1 to 39. At the present time it appears to be 1 to 40. Having had the average ages of death within the bills of mortality in the metropolis calculated from the earliest to the later returns published, they appear to be, as far as they can be made out from the returns, which are only given in quinquennial and decennial periods, as follows:—

Of all returned as having died during the

The average Age was Years, Months. 22 years, from 1728 to 1749 25 1 25 years, from 1750 to 1774 25 6 25 years, from 1775 to 1799 26 0 25 years, from 1800 to 1825 29 0 6 years, from 1826 to 1830 29 10

Thus, whilst it would appear from the proportionate numbers of deaths to the population that the average duration of life in the metropolis has doubled during the last century, it appears from the returns of the average ages themselves that it has only increased four years and nine months, or about one-fifth. The district of the old bills of mortality comprehends little more than one-half of the metropolis. The average age of death for the year 1839 for the whole metropolis, it will have been seen, is only 27 years. So far as an average for that year for the old district can be made out from the several recent district returns, it would appear to be no more than 26 years. But the earlier mortuary registration was known to be extremely defective, especially in the registration of deaths in the poorer districts, and the recent lower averages are ascribable to the closer registration of the infantile mortality in those districts. The earlier returns are only to be regarded in so far as the errors from period to period are likely to have compensated each other; they are only adduced as indicating the degree of proportionate progression, correspondent with the general physical improvements of the population. But the slow general improvement, made up by the great improvements of particular classes, is consistent with the positive deterioration of others. The average age of death of the whole of the working classes we have seen is still no more than 22 years in the whole of the metropolis. In large sub-districts, if we could distinguish accurately the classes of deaths, the average would be found to be not more than half that period: a rate of mortality ascribable to increased over-crowding and stationary accommodation, greatly below anything that probably existed at the commencement of the century. The chief errors in the existing returns are errors which cause the extent of the evils which depress the sanitary condition of the population, and the mortality consequent on those evils to be under estimated.

The erroneous conclusions as to the ages of the populations from the proportions of deaths, have perhaps arisen from assumptions of the existence of states of things rarely, if ever, found, namely, perfectly stationary populations and perfectly stationary causes of death. I have been asked “If 1 out of 40 die yearly, must not the average age of all who die be 40 years?” The answer, by actual experience, as we have seen, is, that it is often not 30 years; and perhaps the reason why it is not so will be most conveniently illustrated by hypothetical cases. For example, let it be assumed that in any given year 40 persons die out of 1600, which is in the proportion of 1 to 40, and in consequence of an unusual prevalence of measles, or some disease to which children are subject, the greater number of deaths occur amongst the infant portion of the population, and hence, out of the 40 deaths, 20 occur at 5 years of age, 10 at 25, and 10 at 60. Then the total existence had, would have been (20 × 5) + (10 × 25) + (10 × 60) = 100 + 250 + 600 = 950 years, and this divided by 40, the number who died would give 950/40 = 24 years nearly as the average duration of life to each of the 40 who died.

On the other hand, suppose a severe winter, in which the peculiar causes of mortality may have pressed unusually heavy upon the older lives, and let the numbers who died have been 20, at 60 years of age; 10 at 40; and 10 at 5; in such case, the total existence enjoyed would have been (20 × 60) + (10 × 40) + (10 × 5) = 1200 + 400 + 50 = 1650 years, which, divided by 40, would give 1650/40 = 41¼ years as the average duration of life to each.

And again, where, in fact, the proportion of death in one year may be represented as 1 death out of 20 of the population; the average existence enjoyed may be greater than when 1 in 40 died for the reason given in the former case. As for example, in the year when 1 in 20 died, it may have happened that the deaths were among the older lives, and that, taking one with another, the average age of all who died might be 50; while in the other case the mortality might have been amongst the infant population, when the average age might have been 20. If the proportion of 1 in 40, or 1 in 20, were to obtain each year continuously, taking one life with another, the average duration to a population just born, of whom 1 in 40 died, and whose place should be supplied each year by a new birth, would be about 20 years to each life, or one-half; and of a similar population, of whom 1 out of 20 died annually, the average duration of life to each would be about 10 years, or one-half the period at the expiration of which all the lives would have expired.

When these examples are considered, it will be understood that the average age of death may remain stationary, or may go on increasing, whilst the proportions of death remain the same, or vary. The actual mortality of most districts is found to be coincident chiefly with its physical condition, and is most accurately measured by the years of vitality which have been enjoyed, _i. e._, by the average age of death. The numbers of deaths increase or diminish considerably, and frequently create erroneous impressions, whilst the average ages of death are found to maintain a comparatively steady course, always nearest to the actual condition of the population, and give the most sure indications.

The chief test of the pressure of the causes of mortality is then the duration of life in years: and whatever age may be taken as the standard of the natural age or the average age of the individual in any community may be taken to correct the returns of the proportions of death in that same community. For example, in the returns of the St. George’s, Hanover Square district, it appears that in 1839, the proportions of deaths was 1 to 50 of the population; but the average number of years which 1325 individuals who died during that year had lived, was only 31 years, or 8 years below the average period of life in Carlisle. There was then in that district during that year a total loss of 10,600 years of life, which at 39 years may be considered as equal to an excess of deaths of 272 persons, and in a healthy state the proportions of deaths should have been 1 in 63 instead of 1 in 50 of the population. The excess in numbers of deaths in the metropolis has been measured by this standard, the total number of years of life, would in a healthy community have been divided in portions of not less than 39 years to every individual who died.

The effect of migration or of emigration, in disturbing the results of returns of the average ages of death in particular localities appears to be commonly much exaggerated.

As formerly, when navy surgeons, overlooking the filth of their ships, which has since been removed, and not perceiving the effects of the atmospheric impurities arising from the overcrowding, which have since been diminished by better ventilation, directed their whole attention to supposed distant causes and mysterious agencies, and were wont to ascribe the whole of the fever which ravaged a fleet to infection from some casual hand, who was found to have been received on board from some equally filthy and ill kept prison where the “gaol fever” had been prevalent; so now, in some of our towns, we find much ingenuity exercised to avoid the immediate force of the facts presented by such returns, by a search for collateral and incidental defects in them. Thus in Liverpool the whole of its vast excess of mortality has been charged upon the poorer passengers who pass through the port. In other towns also, all the excess of deaths from epidemic or infectious disease is charged upon the vagrant population. In New York and some of the American cities, where inquiries have been stimulated by the example of the sanitary inquiry in this country, a common observation made on the proved excess of mortality is, that a large proportion of “foreigners” frequent the city. An inquiry into the cases themselves would generally show that if, instead of the proportion of the immigrant population being: a small per-centage, it formed a very large proportion of the population included: still the proportion per cent. of sickness and mortality, from consumption and other diseases, amongst the resident population, is the greatest; and that even in lodging-houses the disease roost frequently appears first in the occupants who are stationary, and last in the new comers. In some badly conditioned districts, where there is a very severe mortality observable on children, a less proportionate amount of mortality prevails amongst the adults who are migrant, than on other adults resident in somewhat less depressed districts, but who are more stationary. Of all classes (unless it be the higher classes who resort to watering-places) it is not the sickly and the weakly who travel for subsistence as handicraftsmen, or for subsistence in commerce, but the healthy and robust. In so far as the general results of mortuary registration of any district are disturbed by a population who are migrant (who are not only above the average strength, but who generally come with the additional advantage of health by travel in the open air and in a purer atmosphere), they are usually disturbed by unduly raising and giving the locality an appearance of an average of health, and the fatally deceptive chances of longevity that do not belong to it Whilst therefore the localities gain by the average health and strength of the migrant population, other districts have the credit of a share of the excess of disease and mortality which really belong to unhealthy localities. In other words, the population migrating through such districts carry away more disease and mortality from the crowded districts than they take into them. If there had been a mortuary registration at Walcheren, or any pestilential stations productive of an excessive mortality in the army, the registries probably would not have given the localities credit for more than half the mortality which belonged to them. The real sickness and mortality of the more depressed town districts are often made to appear lower than they are by the number of cases treated in distant workhouses, hospitals, and dispensaries, for which no credit is given to the locality where the cause of death occurred.

It would doubtless proportionately enhance the value of such returns as those in question, if the rule were fully carried out that “the population enumerated must always be precisely that which produces the deaths registered;” the grand desideratum being, as expressed by Mr. Milne, for insurance purposes, “to determine the number of annual deaths at each age which takes place among the living at the same age;”[43] but the facts cited of the greater proportion of adults, and of health in those adults who are immigrant, will answer the objections to the superior applicability to local or class insurance tables, deduced from actual local observation of the local rate of mortality prevalent amongst that population, whether migrant or stationary, and without reference to the actual ages of the living (though that were desirable), compared with deductions from any general insurance table, _i. e._ the experience of a distant and wholly unconnected population. Deductions from tables, however correctly made from the experience of other towns, must he, and are proved, by such experience as that hereafter cited, to be merely “guess-work.” Vide ‘General Sanitary Report,’ pp. 218, 219. For myself, I make it a general rule of precaution neither to receive nor adduce statistical returns as evidence without previous inquiry, wherever it is possible, into the particulars on which they are founded, or with which they are connected. I adduce them less as principal evidence, proving anything by themselves, than as proximate measures, or as indications of the extent of the operation of causes substantiated by distinct investigations. The general conclusions which the facts that have come to my knowledge tend to establish on the subject of the experience of mortality are, that there is no general law of mortality yet established that is applicable to all countries or to all classes, or to all times, as commonly assumed; that every place, and class, and period has rather its own circumstances and its own law, varying with those circumstances; that the actual experience of any class or place, or period, even with the disturbance of any ordinary amount of migration, or immigration, or any ordinary influx of young lives from births, is a safer guide than any experience deduced from the experience of another people living at another time and place, or any assumed general law.

For many public purposes, I have submitted it as a desideratum that population returns should give not merely the _numbers_ of each class, or of those engaged in each distinct occupation, which only enables us to resort to the fallacious standard of the proportionate numbers of deaths, to judge of the mortality incidental to the class, but the total ages of each class, which would serve as an index of alterations in the sanitary condition of that same class. Such returns of the total ages should, for the public use, be reduced to their simplest proportions. In the form in which they are usually given, only in intervals of quinquennial or decennial periods, they are extremely meagre, and involve so much inaccuracy in any attempts that might be made to use them, for the purpose of comparing district with district, as to be generally useless. Whereas, if the ages of any class, or of the general population living in any district, and the ages of those of them who die, were reduced to the simplest proportions—that is, if the total years of age, whether of the living or dying, were divided by the total number of individuals from which the returns were made, the public would be enabled to make comparisons between district and district, and to judge of the relative degrees of pressure, in each, of the causes of mortality. As the simple proportions of average ages of the living have not yet, that I am aware of, been used, or even calculated in any instance, I beg leave to exemplify them.

Mr. Griffith Davies is theoretically of opinion, on a formula of De Moivre, that in general the average age of death in any community is necessarily higher than the average age of those living in the same community: and that in a stationary population the average age of death will, under ordinary circumstances, be in the ratio of 3 to 2 higher than the average age of the living. I have had the average age of the living population, on which the experience embodied in the Carlisle Insurance table was founded, calculated: and if that may be considered to have been a stationary population, the proportion of the ages of the living to those of the dying was practically as about 3 to 4: for whilst the average age of the dying was 38–3/10, the average age of the living population was 32–9/10. The average age of the dying in Hereford, in which the increase of population had been very slight, was 39. But the average age of the living population, so far as it can be made out from quinquennial returns, was 28 years and 5 months. On this and all returns of the ages of the living, in the mode in which the returns have been collected, allowance must be made for understatements of ages by some of the adult members of the community. On the whole, the proportion of the ages of the living to the dying appears to be in an ordinarily healthy and stationary community, as about 3 to 4.

As yet the observations have not been on a sufficiently wide basis; but it appears that wherever there is any divergence between the average ages of the living and the average ages of the dying, the divergence beyond their natural proportions may be taken as indicating the proportionate operation of some disturbing cause upon either line, as by some extraordinary increase of births, or by immigration or emigration, on the average ages of the living, and on the line of the average ages of the dead.