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rates in 1901-5. The improvement was thus markedly greater
than that in the general death-rate for all ages, which dropped in
the same period to 90 per cent, of its level in 1901-5.
The death-rate for the school child (5—15 years) has remained
practically constant throughout the whole period; it is not clear
whether the slight rise of recent years shown in the table has any
significance. The death-rate during this healthy period of life is
in any case a very low one, and it is possible that it approaches the
minimum attainable.
The statistical analysis of the variations in the chief individual
factors in the mortality of infancy and childhood set out in the
table on page 43 may be summarised as follows : —
(a) Diarrhoea and Enteritis, formerly very potent factors in
the infant death-rate, have become much less prominent causes of
death. The death-rate from these conditions dropped in the years
1916-21 to some 30 per cent, of its level in 1901-5, while it
accounted in the earlier period for one-fifth, and in the later one for
one-tenth of the total infant mortality.
Approximately the same decrease in mortality is shown at the
ages 1—5.
The table shows that epidemic diarrhoea became steadily and
rapidly a diminishing factor in the death-rates at ages 0—1, and
somewhat less steadily at ages 1—5; this change in its importance
relative to other factors, became most evident during the years
1916-21.
(b) Acute Infectious Diseases. The death-rate from the
group of acute infectious diseases specified in the table dropped
during the 21 years to 28 per cent, at ages 0—1, 47 per cent, at
ages 1—5, and 57 per cent, at ages 5—15 of their levels at the corresponding
ages in 1901—5. The acute infectious diseases have
throughout been a relatively small factor in the mortality among
infants under 1, and have evidently become steadily less important.
They are, however, responsible for a large part—roughly onefifth—of
the death-rate in early childhood and during school-life;
in both there has been a satisfactory decrease both in the actual
death-rate produced by these diseases and in their relative importance
in comparison with other factors. The decrease has not been
a steady one, as might be expected from the occurrence of
epidemics in cycles of years.
Examination of the data for the individual infectious diseases
shows that:—