View report page

48
On the whole study of the first section of the diagram shows that diphtheria and scarlet fever
prevail abnormally in a borough during one and the same year or series of years. The diagram further
shows that the west, north and central boroughs suffer on the whole relatively lightly, the east and south
heavily. Again, in the eastern boroughs there is indication of an early, middle and late series of
heavy years with intervening periods of comparative freedom, a phenomenon more conspicuously
exhibited in the second and third sections of the diagram. Study of this first section reveals, moreover, a
tendency for diphtheria and scarlet fever to spread from one borough to adjoining boroughs. Thus
Poplar begins to suffer excessively from diphtheria in 1901, as compared with London as a whole, and then
in 1904 Stepney and Bethnal Green become involved. Later Poplar again suffers in 1913; Stepney
and Bethnal Green respond in 1914; and in 1915 Shoreditch is also affected. In the case of scarlet
fever, excess prevalence apparently travels from Lewisham (1902 and 1903) affecting Woolwich in 1903
and 1904 ; or again, it proceeds from Lewisham in 1909-10 to the adjoining borough, Greenwich, in 1911
and 1912. This slow migration from borough to borough or from one part of the town to another is a
phenomenon long familiar to those who have studied diphtheria and scarlet fever (and it may be added
measles also) in London.
Examination of the first section of the diagram further shows that in certain boroughs the incidence
of diphtheria has been in excess of that in London as a whole for a long series of years. Thus,
Fulham had a sequence of 11 years of excess; Woolwich, 10 years; Greenwich, 9 years; Stepney, 8
years; and Lewisham, 7 years. Similar sequences of excessive incidence are not shown to the same
extent in the case of scarlet fever, although Deptford had 8 years of excess and Bethnal Green 6 years.
These periods of excessive incidence of diphtheria stand in suggestive relation with devotion of special
attention to bacteriological examination; there can be no doubt, for example, that the Fulham and
Woolwich sequences owe some of their prominence to the fact that during the years in question, very
assiduous use of laboratory methods was made.
The point which the second section of the diagram more especially illustrates is the extent to
which high incidence of the two diseases may occur simultaneously in the several boroughs. This
phenomenon is discernible in section one, but is more marked in sections 2 and 3. It will be seen that
in the case of scarlet fever (in section two) there is a conspicuous grouping of high rates in 1901-2,
1905-9 and 1913-15 throughout London, with low incidence in the intervening and succeeding years.
This feature is not quite so pronounced in the case of diphtheria.
The third section of the diagram brings into prominence those boroughs in which the incidence
of either disease is in excess compared with London. It is noteworthy that the eastern and southeastern
boroughs are those in which the greatest excess over the London average is exhibited. This
fact is also clearly shown in the first section of the diagram.
Movement of population may have had something to do with the contrasts here presented. In
the period 1901-1910 there was a considerable influx into Fulham of poorer working class persons
displaced from Chelsea by demolition of old houses, and there may be some connection between this
and the continuously high diphtheria rate, although it would certainly be expected that the scarlet
fever rate would also have been in excess The importance attached to bacteriological diagnosis in diphtheria
during the years in question certainly, however, played some part here as already noted In Stepney
for a number of years preceding 1905 there was a large influx of immigrants—mainly Russian—so much
so, that the native population was actually displaced. This immigration was arrested by disturbed
conditions in Russia in 1906 and also by the Immigration Act. Furthermore, in Woolwich, Lewisham
and Greenwich (up to about 1912) large numbers of dwellings for the working class were erected annually,
and this fact may have had bearing upon the excess shown in this part of London. On the other hand
Wandsworth has added even more than these boroughs to its population, without showing corresponding
excess. It is, however, very difficult to assess the type of population concerned in these movements ;
undoubtedly outward migration from central areas has been mainly among growing families and thus
the districts opened up would have their child population of susceptible ages augmented annually to a
disproportionate extent as compared with areas not affected by such movements; in addition the
possibility of such families carrying infection with them cannot be altogether excluded.
High incidence of scarlet fever in new districts is not, as already remarked, confined to London,
but there are practically no new districts north of the Thames within the County boundary comparable
with those in the south eastern area, and to this fact is probably due the relatively small number of
boroughs in the west and north of London in which excessive incidence occurs. In the main, the outward
movement in this area has been over the County boundary. About 40 per cent. of "Londoners
live outside the County, and this fact must be taken into account when comparisons are made between
the distributions of these diseases in London, in Glasgow and in Birmingham, since the boundaries of the
two last named cities have been extended as the cities have grown; high incidence of scarlet fever upon
their outer districts is not infrequent, but in London north of the Thames the exact reverse of this is
exhibited. (See sections I. and III. of the diagram.)
Examination of the three sections, therefore, presents the facts for London, seen as it were from
three different angles, and appears to justify the following conclusions.
1. There is a marked tendency for diphtheria and scarlet fever to prevail concurrently
and to travel from one part of the town to neighbouring parts.
2. There is reason for thinking that the central and poorer parts serve as reservoirs
of disease from which epidemic prevalence spreads to newly inhabited outlying areas.
3. Any generalisation to the effect that scarlet fever and diphtheria tend especially to
affect well-to-do as contrasted with poor areas is not justified by London experience.