293 | 32 | 325 |
+---------------+-------------+----------+-------------+

The combined figures for diphtheria and croup in later years
are:--(1900) 316; (1901) 296; (1902) 255; (1903) 195; (1904) 184;
(1905) 174; (1906) 190; (1907) 175; (1908) 166.

Several facts are roughly indicated by the table. It begins with an
extremely severe epidemic, which has not been approached since. Then
follows a fall extending over twenty years. On the whole this diminution
was progressive, though not in reality so steady as the decennial
grouping makes it appear, being interrupted by smaller oscillations in
single years and groups of years. Still the main fact holds good. After
1880 an opposite movement began, likewise interrupted by minor
oscillations, but on the whole progressive, and culminating in the year
1893 with a death-rate of 389, the highest recorded since 1865. After
1896 a marked fall again took place. This is partly accounted for by the
use of antitoxin, which only began on a considerable scale in 1895, and
did not become general until a year or two later at least. Its effects
were only then fully felt. The registrar-general's returns record
mortality, not prevalence--that is to say, the number of deaths, not of
cases.

On the whole, we get clear evidence of an epidemic rise and fall, which
may serve to dispose of some erroneous conceptions. The belief, held
until recently, that diphtheria is steadily increasing in Great Britain
was obviously premature; it did rise over a series of years, but has now
ebbed again. Moreover, the general prevalence during the last thirty
years has been notably less than in the previous twelve years. Yet it is
during years since 1870 that compulsory education has been in existence
and main drainage chiefly carried out. It follows that neither school
attendance nor sewer gas exercises such an important influence over the
epidemicity of diphtheria as some other conditions. What are those
conditions? Dr Newsholme has advanced the theory, based on an elaborate
examination of statistics in various countries, that the activity of
diphtheria is connected with the rainfall, and he lays down the
following general induction from the facts: "Diphtheria only becomes
epidemic in years in which the rainfall is deficient, and the epidemics
are on the largest scale when three or more years of deficient rainfall
follow each other." He points out that the comparative rarity of
d