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10
Experience gained from the notification of diphtheria.
The experience gained from the notification of infectious diseases is especially valuable in
connection with the subject under consideration.
The statistics of notification of infectious disease only extend back to the year 1890, and it was
not until 1892 that the age of the patient was required to be stated on the certificate. I have already
published in annual reports diagrams for the years 1893-4-5-6, showing the number of cases
notified in each week in relation to the mean of the year at the ages 0-3 years, 3-13 years, and 13
years and upwards. These diagrams I now reproduce, and to them have added a similar diagram for
the year 1892.† In studying the prevalence of diphtheria in successive weeks the following facts
should be borne in mind—
1892. The schools of the London School Board closed generally for the summer holiday
on Thursday, the 21st July, in the 29th week, and re-opened on Monday, 22nd August, i.e.,
the beginning of the 34th week. Comparison between the number of cases at the several
ages in three periods of four weeks (1) the 27th-30th week, (2) the 31st-34th week,* and (3)
the 35th-38th week, gives the following results—
Under 3 years. 3-13 years. 13 years and above.
Increase or decrease per cent, of number of cases
in 2nd period in relation to number in 1st
period +20 —3 —10
Increase or decrease per cent, of number of cases
in 3rd period in relation to number in 2nd
period —7 +29 +34
1893. The schools of the London School Board closed generally for the summer holiday
on Thursday, 27th July, in the 30th week, and re-opened on Monday, 28th August, i.e., at
the beginning of the 35th week. Comparison of the number of cases at the several ages
in three periods of four weeks (1) 28th-31st week, (2) 32nd-35th week,* and (3) 36th-39th
week, gives the following results—
Under 3 years. 3-13 years. 13 years and above.
Increase or decrease per cent, of number of
cases in 2nd period in relation to number in
1st period +8 —27 +1
Increase per cent, of number of cases in 3rd
period in relation to number in 2nd period +6 +81 +33
1894. The schools of the London School Board closed generally for the summer holiday
on Thursday, 26th July, i.e., in the 28th week, and re-opened on Monday, 27th August, the
beginning of the 35th week. Comparison of the number of cases at the several ages in the
three periods (1) 28th-31st week, (2) 32nd-35th week,* (3) 36th-39th week gives the
following results—
Under 3 years. 3-13 years. 13 years and above.
Decrease per cent, of number of cases in
2nd period in relation to numbers in
1st period +11.0 —23.9 +4.1
Increase or decrease per cent, of numbers
of cases in 3rd period in relation to
number in 2nd period —10.6 +44.5 +10.8
1895. The schools of the London School Board closed for the summer holiday on
Thursday, 25th July, i.e., in the 30th week, and re-opened on Monday, 26th August, i.e.,
the beginning of the 35th week. Comparison between the number of cases at the several
ages in three periods of four weeks (1) the 28th-31st week, (2) 32nd-35th week* and (3)
36th-39th week gives the following results—
Uuder 3 years. 3-13 years. 13 years and above.
Decrease in number of cases in 2nd period
in relation to numbers in 1st period —21.5 —36 —16.4
Increase in number of cases in 3rd period
in relation to number in 2nd period +6.5 +49 +15.8
1896. The schools of the London School Board closed generally for the summer holiday
on Thursday, the 23rd July, in the 30th week, and reopened on Monday, the 24th August,
that is, the beginning of the 35th week. Comparison between the number of cases at the
several ages in three periods of four weeks, (1) the 28th-31st week, (2) the 32nd-35th week,*
and (3) the 36th-39th week, give the following results—
Under 3 years. 3-13 years. 10 years and above.
Increase or decrease per cent, of number
cases in 2nd period in relation to number
in 1st period —9.4 —14.9 +4.5
Increase or decrease per cent, of number
of cases in 3rd period in relation to number
in 2nd period +18.8 +34.0 —7.3
* In these and other tables in the report where similar comparisons are made, the middle period of four weeks, i.e.t the period of
"holiday influence" commences and terminates one week later than the actual holiday period, in order to allow as far as possible for
" incubation period " and delay in notification.
† Since this report was in type, it has been possible to supply the diagram for the year 1897. The particulars relating to the
school holidays in 1897 are as follows—
1897.—The schools of the London School Board closed generally for the summer holiday on Thursday, the 22nd July, in the
29th week, and re-opened on Monday, the 23rd August, that is, the beginning of the 34th week. Comparison between the number of
cases at the several ages in three periods of four weeks (1) the 27th-30th week, (2) the 31st-S4th week, and (3) the 35th-38th
week give the following results—
Under 3 years. 3-13 years 13 years and upwards.
Increase or decrease per cent. of number of cases in 2nd period in relation
to number in 1st period —8.9 —28.7 —12.0
Increase or decrease per cent. of number of cases in 3rd period in relation
to number in 2nd period —0.7 +30.4 +6.4