Group I.-No back-to-back houses 8,713 27.5 Green- Group II.-Average proportion of 23 per cent. of back-to-back gates Sub-houses. 6.6 2.8 4.5 1.42 Group I.-No back-to-back houses 54,264 26.1 Sub Dis trict Group III.-Average proportion 4,380 37.3 8.6 4.5 7.6 2 83 It will be seen that the mortality from all causes, from pulmonary diseases, from phthisis, and from the seven chief zymotic diseases taken together, as well as from diarrhoea alone, increase pari passu with the proportion of back-to-back houses. Causes of High Mortality with Increased Density. The higher death-rates, which go hand in hand with increased density of population, are not the direct results of the latter. The crowding of persons together doubtless leads to the risks of fouling of air and water and soil, and to the increased propagation of infectious diseases, and thus directly affects the mortality. But these "direct consequences of close aggregation are probably as nothing in comparison with its indirect consequences or concomitants. The more crowded a community, the greater, speaking generally, is the amount of abject want, of filth, of crime, of drunkenness, and of other excesses, the more keen. is the competition, and the more feverish and exhausting the conditions of life; moreover, and perhaps more than all, it is in these crowded communities that almost all the most dangerous and unhealthy industries are carried on. It is not so much the L aggregation itself, as these other factors which are associated with aggregation, that produce the high mortality of our great towns or other thickly populated areas" (Ogle). (1) Of the direct influences connected with close aggregation of population, filth conditions of air and water and soil are the most important. If the source of water supply is pure and the drainage is good, densely populated towns may be, and are, commonly better off in these matters than rural districts. But atmospheric impurities, especially in the form of decomposing organic matter, are doubtless more rife in town than in country; and Dr. Farr rightly lays special stress on these. Even in towns the amount of such impurities varies greatly in houses of different sizes, and such differences throw a flood of light on the facts already given regarding the higher mortality in one and two-room houses. The following table, given in a paper which appeared in the Philosophical Transactions for 1887, by Professor Carnelly and Drs. Haldane and Anderson, as the result of elaborate observations made at Dundee, shows very strikingly the differences in houses of varying size. Taking the average amount (in excess of outside air) of carbonic acid, organic matter, and micro-organisms, respectively, in the atmosphere of houses of four or more rooms as unity, then in one and two-room houses, the relative amount was as follows: (2) The more rapid spread of infectious diseases is shown by the higher zymotic mortality in large towns, their more rapid spread being partly due to the shorter distance the infection has to travel from individual to individual, and partly, also, to the fact that a fouled state of the atmosphere and soil facilitates the propagation of infection. (3) Other diseases, as phthisis, are more common in urban than in rural districts. The close connection between phthisis and a foul atmosphere is well established. Dr. Anderson's researches in Dundee, and Dr. Russell's in Glasgow, both show that the mortality from phthisis in these towns is highest among the inmates of three-room houses; and the explanation suggested by the former is probably correct, that the high infantile mortality from other forms of tubercular disease returned as nervous diseases, atrophy, wasting, etc., prevents the growth of young adults (who are most prone to tubercle of the lungs) in the smaller houses. (4) Poverty of the inhabitants of densely populated districts, implying as it does inadequate food and deficient clothing and shelter, has a great effect in swelling their mortality. Dr. Drysdale, in a paper read at the meeting of the British Medical Association in 1887, quotes as evidence of the importance of indigence as a cause of a high death-rate the lower mean age at death of the working classes (this is fallacious; see page 314); and the fact that in France 65 per 1,000 deaths among the rich are due to tubercular diseases, and 250 per 1,000 among the poor. In Dublin, Dr. Grimshaw states that in 1886 the death-rate per 1,000 living was 13.4 among the independent and professional classes, and 33.7 among the "service classes." (5) Other evil social conditions commonly accompany poverty. Cities are commonly the hotbeds of vice and misery, of crime and drunkenness, as well as of filth and want. The Select Committee on Intemperance (4th Report, 1878) say: "On the whole, in the towns where the drunkenness is greatest, the population is most dense." The density of population and the drunkenness each of them probably stands in the place of both cause and effect. Accidents are more common and more fatal in cities than in the country. The evil influences of heredity should also be mentioned, the organism tending to degenerate when placed, generation after generation, in an unwholesome environment. (6) The influence of occupation and of homes involving exposure to poisonous effluvia and other poisonous agencies will be considered in the next chapter. CHAPTER X. EFFECT OF OCCUPATION ON MORTALITY. Class and Occupation.-Difficulties of Classification. -Methods of Comparison between Occupations.-Fallacies of Mean Age at Death.-Dr. Ogle on Occupational Mortality.--Sources of Possible Error.-Mortality in Individual Occupations.-Comparative Mortality Figures.-Causes of Mortality in Different Occupations.-Influence of Foul Air and Dust.— Alcoholism and Lead-Poisoning. CLA LASS and Occupation.-At the census of 1841 and more completely at the subsequent census enumerations, each individual was classified under his principal occupation on the census day, with distinction of age and sex. The distinction of age is important, as it enables us to compare the number living in each well-defined occupation with the number who are registered as dying at the corresponding ages, and thus to determine the influence of occupation on health and life; and also because it enables us to determine whether those engaged in any particular occupation are children, or young or old adults, which information has important social bearings. Twentyfour orders of occupation are described by the RegistrarGeneral, which comprise 80 sub-orders or genera. The orders are grouped into six classes; viz., professional, domestic, commercial, agricultural, industrial, and non-productive.* The population may be divided roughly into two great groups,those who work, and those who professedly have no definite occupation. After due allowance has been made for those who are infirm, or have retired in advanced age from their occupations, the number belonging to the second class in this country See Appendix I. (p. 315) for a tabular statement of the number following each of these groups of occupations. |