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CHAP. III
LONDON SMALL-POX
33

living are indicated at the two ends and in the centre, the last four years of the Bills of Mortality being omitted because they are considered to be especially inaccurate. The upper line gives the total death-rate from all causes, the middle line the death-rate from the chief zymotic diseases—measles, scarlet-fever, diphtheria, whooping-cough and, fevers generally, excluding small-pox, and the lower line small-pox only. The same diseases, as nearly as they can be identified in the Bills of Mortality according to Dr. Creighton, are given in the earlier portion of the diagram from the figures given in his great work, A History of Epidemics in Britain. With the exception of these zymotics the diagram is the same as that presented to the Royal Commission (3rd Report, diagram J.), but it is carried back to an earlier date.

Let us now examine the lowest line, showing the small-pox death-rate. First taking the period from 1760 to 1800, we see, amid great fluctuations and some exceptional epidemics, a well-marked steady decline which, though obscured by its great irregularity, amounts to a difference of 1,000 per million living. This decline continues, perhaps somewhat more rapidly, to 1820. From that date to 1834 the decline is much less, and is hardly perceptible. The period of Registration opens with the great epidemic of 1838, and thenceforward to 1885 the decline is very slow indeed; while, if we average the great epidemic of 1871 with the preceding ten years, we shall not be able to discover any decline at all. From 1886, however, there is a rather sudden decline to a very low death-rate, which has continued to the present time. Now it is alleged by advocates of vaccination, and by the Commissioners in their Report, that the decline from 1800 onwards is due to vaccination, either wholly or in great part, and that the marked decline of small-pox in the first quarter of the present century affords substantial evidence in favour of the protective influence of vaccination."[1] This conclusion is not only entirely

  1. Final Report of Roy. Comm., p. 20 (85).