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and out of London, for immigrant females out-number in increasing degree
immigrant males, and if, as is usually assumed, rural immigrants have had less
exposure to infection than is experienced in London, a higher and increasing
average age of attack among females would be expected.
Of the total number of cases of diphtheria notified in 1922 numbering 15,304
(52 weeks), 7,349 or 48 per cent. were among children aged 5.15 years, of whom
420 or 5.7 per cent. died. The corresponding percentages for 1921 were 56 per cent.
and 5.4 per cent. respectively.
Of the total of 17,226 cases of scarlet fever notified in 1922 (52 weeks), 10,331
(60 per cent.) were of ages 5.15, of whom 86 ('8 per cent.) died. The corresponding
percentages for 1921 were 68 and .5 per cent. respectively. The higher scarlet
fever case mortality of 1922 is mainly accounted for by the increased death-rate
which has been observed during the prevalence of epidemic influenza.
Whooping-cough and measles were both prevalent in 1922, and the deaths at
ages 5-15 were 26 and 83 respectively.
Diphtheria.
Cases of diphtheria occurring among children in the Council's schools numbered
5,641. The geographical distribution corresponded broadly with that of scarlet
fever, except that in two boroughs in the east-end (Poplar and Bethnal Green) the
earlier prevalence of 1921 in the case of diphtheria, did not abate to any extent.
During the year 257 investigations were conducted by assistant medical officers
affecting 155 schools. The total number of bacteriological examinations made in
the department in connection with diphtheria amounted to 5,401, of which 471
showed the presence of diphtheria bacilli, whilst 377 aroused some suspicion. The
remainder were negative. During the course of the year 251 new "carrier" caseswere
discovered. The relationship of the 1922 diphtheria curve to that of 1921 is
generally similar to that of 1894 to 1893, but the total incidence in 1922 was considerably
higher than in 1894. Diphtheria in 1922 presents less satisfactory
features than scarlet fever; although the autumnal increase did not approach the
height of the preceding two years the total incidence did not proportionately
decline; towards the close of the year, however, signs of the marked decrease which
has occurred in the opening month of the present year are discernible. In the
records of previous years evidence is found of coincidence of epidemic prevalence
of scarlet fever and diphtheria; and a tendency is observable for the diphtheria
prevalence to lag somewhat upon that of scarlet fever. The influence of rainfall
upon both diseases has been discussed in earlier reports, and the low rainfall of
1920 and 1921 happening at a time when the population contained a large proportion
of susceptible children may, in the light of earlier experience, be largely
responsible for the exceptional recent incidence of both diseases. As compared,
however, with earlier years, diphtheria has proportionately to scarlet fever been
in excess; and one circumstance which certainly cannot be left out of account as
sharing in the increase of diphtheria is the greater number of cases brought to light
by wider use of bacteriological methods of detection, which are not available in the
case of scarlet fever. The bacteriologist of the Metropolitan Asylums Board, Dr.
Cartwright Wood, in his annual report for 1921—2 states that 997 cases were admitted
to the hospitals of the Board in which diphtheria bacilli were present, but
which manifested no clinical evidence of the disease, thus 6.4 per cent. of the cases
dealt with in 1921 would not have been notified in the nineties. Some part, therefore,
of the increase of diphtheria in London during more recent years must be
attributed to the more intimate surveillance rendered possible by bacteriological
methods.
From the annual reports of borough medical officers of health it appears that
the proportion of bacteriological cases of diphtheria varies greatly in different districts.
In Kensington in 1921, 465 specimens were examined, of which 87 were
positive; the total cases notified during the year was 376. In Lambeth, of 734
examinations, only 15 gave positive results, the total cases notified during the year