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cases, although the actual number of notified cases may be small. The fact, however, that the disease
is contracted at school considerably modifies the age incidence of the cases, although their fewness
may obscure the cause. This change in the age incidence may, however, be followed by a definite
outbreak undeniably due to infection at school, and of considerable magnitude.
Tho behaviour of diphtheria in recent years in Lewisham is illustrative of the way in which
there may be, in successive years, with decreasing prevalence, increase of incidence of disease upon
children of the school age manifested finally in a recognised outbreak of the disease among tho
children of a particular school. Thus the number of cases aged 3.13 years per cent, of total
cases notified in Lewisham in successive years has been as follows—

The increasing incidence of the disease upon children of school age from 1893-96 is conspicuous,
although the prevalence was in the first three years diminishing, and certainly no question of
nomenclature can be held responsible for this alteration in age incidence. It will be recollected that
this increasing incidence upon the school age culminated in 1896 in a disastrous outbreak of diphtheria,
which Dr. Hamer, who enquired into the matter on behalf of the London County Council, conclusively
showed to be due to infection in the Lewisham-bridge Board School and the St. Stephen's
National School. The circumstance that appeared to be principally operative in bringing this outbreak
to an end was the detention of children from school by their parents. The disease in the subsequent
year became less prevalent, and the incidence upon the school age less marked ; but in the two most
recent years, both prevalence and incidence on the school age have increased. The question arises
whether infection at school is again responsible for the large prevalence of 1899.
In that year there was especial prevalence of this disease in two contiguous areas* marked AC
and AG3 on the map of the London School Board (West Greenwich division), and examination of the
weekly notification returns issued by tho Metropolitan Asylums Board supplies the following figures—
The number of cases notified in each successive four weeks in these areas, from the 20th to the
47th week inclusive, was 12, 43, 24, 5, 13, 23 and 23. The smallest number of cases (5) occurred in
the four weeks (32nd to 35th) in which the effect of the closing of the schools for the summer holiday
would be most felt.
The prevalence of the disease among the two sexes of the age 3-13 is also deserving of notice,
thus, from the 25th to the 31st week the number of boys of this age attacked was 12, the number of
girls 29. During the weeks of holiday influence, i.e., from the 32nd to the 35th weeks inclusive boys
escaped, but three girls were attacked; from the 36th to the 41st weeks inclusive only two cases
occurred among boys although eight girls were attacked, and from that time to the end of the year
17 boys and 16 girls were attacked. A local prevalence of diphtheria, which diminishes in material
degree during the period of school holiday influence, and in which girls are attacked at one period
and boys at another, undoubtedly raises question whether attendance at school is not an important
factor in the spread of the disease.
Diphtheria—Proportion of cases and deaths in hospital.
Diagram X., (page 25), shows the proportion of London cases of diphtheria admitted into the
hospitals of the Metropolitan Asylums Board during each of the years 1890-99 inclusive, and the
proportion of deaths from this disease which occurred in these institutions during each of the years
1888-99. It will be seen that these proportions were greater in 1899 than in any previous year.
Diphtheria—Age and sex distribution.
The following table shows the cases, deaths, case rates, death rates, and fatality of diphtheria
at the several ages and for each sex in London in 1899. As in preceding years, the incidence of
attack at " all ages " on females was greater than on males, but the incidence of death at " all ages "
was the same on both sexes, the fatality of males being greater than that of females. In the age groups
adopted for the purposes of this table, the incidence of attack was greatest upon males and females of
four years of age and the incidence of death was greatest upon males and females of one year of age.
The greatest fatality occurred among males and females during the first year of life.
* These areas include a small portion of the parih of Lee.
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