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that in London the mortality from influenza has not, wholly counterbalanced the gain due to
the diminution in the mortality from other causes. The result will therefore probably be that the
population of London as compared with the other communities will be a little less favourably situated
than the figures and diagram show.
The life table for the period 1891-1900, has been the work of Mr. G. H. Day, assisted by
Mr. M. O'Carroll, officials of the Public Health Department. This is the first extended life table for
the London population which has been published, and on that account it is necessary that the method
of construction should be set out in some detail. The value of the present table for comparative
purposes will be greatly enhanced when similar tables have been constructed for future decades, and
when the time arrives for the construction of these tables, it will be a matter of considerable
importance that the method of construction adopted for the present table should be known, in order
that these life tables may be constructed as far as possible on similar lines. For this purpose the
following statement by Mr. Day of the method adopted and formulas used has been included, and
I desire also to acknowledge the services of Mr. A. C. Waters, of the General Register Office, who has
made a number of valuable suggestions as to the statement.
Construction of the London Life Table 1891-1900.
The facts upon which this life table is based are supplied by the census enumerations of 1891
and 1901 as to the age and sex constitution of the London population in the Registration County of
London, and the records of mortality relating to the same area for the decennium 1891-1900.
Deaths.
An initial difficulty which presented itself in the construction of this life table is due to the
fact that it was found impracticable to obtain the deaths at the various age periods which properly
belong to the London population for the whole of the decennium. Nearly 30 per cent. of the total
deaths registered in London occur in public institutions, and many of the persons dying in these
institutions previously resided outside the London area, and such deaths should properly be excluded
for the purposes of a life table. Again, there are a number of institutions, lunatic asylums, workhouses,
convalescent hospitals, etc., situated in the immediate vicinity of London but outside the
London area, which are mainly filled by persons formerly resident in London, and the deaths
occurring in such institutions should properly be credited to the London population although
they are registered elsewhere. Since the year 1885 the Registrar General in the Annual Summary
of Births and Deaths in London and other large towns, has published the number of deaths at
"all ages," corrected for institutions, but these numbers, beyond giving the material for finding
the total deaths in the decennium at "all ages" properly belonging to the London population
are of little value for the purposes of life table construction. What is required for this purpose
is the number of deaths at each age period corrected for institution deaths, and these figures are
not published in the Registrar-General's reports. During the four years 1897-1900, however, for the
purposes of the annual reports of the medical officer of health, the number of deaths at each age period
properly belonging to the London population have been obtained from the records of the RegistrarGeneral,
and these figures furnish material for estimating the effect of the disturbing influence of
institution deaths. In the construction of the life table the deaths for the four years 1897-1900 at
each age period fully corrected for institution deaths have been applied to the uncorrected deaths at
each age period as published in the Registrar-General's annual reports for the 10 years 1891-1900, and
the resulting figures may be taken to represent with sufficient accuracy the deaths in the 10 years
1891-1900 properly belonging to the London population; in any case the figures so obtained are
very much nearer the actual facts than the uncorrected figures published by the Registrar-General.
The following table shows the deaths at each age period so obtained upon which the life table is
based—