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46 Annual Report of the London County Council, 1913.
and countries in which conditions have been less favourable, in the matter of phthisis death rates; thus
in Europe, England and Germany show great reduction and this began earlier in England than in
Germany; Ireland, Norway and Hungary show actual increase; other countries occupy an intermediate
position.
Examination of the curves for England and Wales, Prussia, the United States and Ireland in the
light of the foregoing observations, may now be made. All four curves present a slight protuberance
corresponding to the age 20-25 males and 15-20 or 20-25 females; it is possible that this may be in
part produced by movement of population, which would be especially likely to cause disturbance in the
figures at the age period when emigration is specially high, and the likelihood of movement of sick
persons outward, or, on the other hand, of dying, persons to their original homes, would be particularly
manifested. The curves for all the countries show that males suffer more than females, but if examination
be instituted into the decrease in mortality in the ten years 1901-1911 (as measured by the area
between the outline for 1901 and that for 1911) it will be seen that while in England and Prussia the
total decline in incidence upon males exceeds that upon females, the reverse is found to hold in America,
where, moreover, decrease in male incidence falls short of that among males both in Prussia and England.
It may be that there is here reason for suspecting that in numerous instances, more particularly among
the male emigrants to the United States, there have been included persons suffering from early phthisis
and the precautions recently insisted upon with regard to medical examination on landing may thus find
some justification. Conclusions, however, on this point so far as the American figures are concerned,
must be regarded with some reserve, as the "Registration Area" of 1901 has been since extended, and
consequently the rates are not strictly comparable. (The Registration Area in 1911 comprised some threefourths
of the total population of the United States.) In the more recent years there is a marked tendency
for the curves in both sexes to approximate to a more or less common type. In the earlier years,
on the other hand, the differences of type are very marked. This is probably due in large measure,
as already indicated, to other causes than the influence of movement of population, but this factor has
doubtless also made itself felt in various ways. At one extreme stands the Irish curve with its highest
incidence at 20-25 or 25-35; at the other extreme the Prussian curve with its maximum at 60-70. The
England and Wales curve shows in the earlier years greater similarity to the Irish type, but in the later
years it and the Prussian curve more nearly approximate to one another. Now, it is particularly interesting
to note that if the England and Wales figures be dissected, by separating out the urban and rural
counties from each other, the rural counties conform fairly closely to the Irish type while the urban
conform more closely to that of Prussia. It would seem then, on the whole, that the following conclusions
may be drawn :—
1. In the case of Ireland (and in less marked degree the phenomenon is apparent in the rural
counties of England and Wales) there is specially noteworthy incidence upon young adults; this may
be in part due to the fact that the more vigorous units of population have been removed; leaving behind
a population which is less resistant to disease, and in part due to return to the original home when fatal
illness develops of a certain number of those who had emigrated.
2. In the case of England and Wales the exceptionally favourable rates as compared with the
other countries are no doubt in part attributable to the unique facilities which have existed for enabling
those affected by early phthisis to go abroad, with the result that the deaths when they have ultimately
occurred have not prejudically affected the death rates recorded in this country. Conversely, the United
States curves, particularly those of males may have been, to some small extent, prejudicially affected by
addition of such deaths. In Germany and to a less marked extent in England and Wales, the growth
of the sanatorium movement has doubtless led to a certain number of patients who might otherwise
have gone abroad remaining to be treated at home. The extent of the influence thus exerted can
scarcely have been as yet such as to appreciably affect the curve in this country at any rate. As
regards Germany there seems at no time to have been so great a tendency, as has existed undoubtedly
in this country during the last half century, for consumptives to go abroad.
3. The very heavy rates at the higher ages in Prussia and the rise in the incidence rates at the
highest ages in the United States are doubtless due in the main to peculiarities of fashion in nomenclature
which have already been fully discussed. It may, however, be here noted that the type in both
these curves is rather suggestive of the urban as distinguished from the rural curve of England and
Wales, and it may be that the high degrees of urbanisation in Prussia and in the United States registration
area have not been altogether without influence in this connection.
The outstanding lesson to be drawn from this examination of age-incidence of tuberculosis in
different countries is, it may now be urged, that emphasis should be placed upon the very variable connotation
of the expression tuberculosis at different times and in different countries. The huge contrasts
presented by the German and English curves, in corresponding years, seem to be in large degree thus
explained, and it cannot be doubted that variations in tuberculosis mortality, in one and the same county
at different times, are also in very large degree similarly accounted for.
With a view to seeing whether any further light would be thrown upon the tuberculosis curves,
examination of the similar curves for cancer has been made. In Diagram V the incidence of cancer
mortality in England and Wales, Prussia, the United States Registration Area and Ireland is shown.
Incidentally it may be noted that the fall at the highest ages (70 and upwards) in Prussia is probably
in the main due to the higher percentage of cases returned as "altersschwache" (or senile debility) at
these ages, while the falling away of the curve for 1911 in the case of the highest ages in Ireland is
probably in the main a result of disturbance in the statements as to age resulting from the introduction
of old age pensions. The broad deductions, however, to be drawn from the cancer curves are first,
that cancer can have caused but little interference with the types of tuberculosis curves which have