250 THE WONDERFUL CENTURY. CHAP. xvm. 



later on, measles, which was insignificant before the 

 middle of the seventeenth century, began to replace the 

 latter disease. In order to show the actual state of the 

 mortality from these diseases during the epoch of regis- 

 tration, I have prepared a diagram (II.) giving the death- 

 rates for London of five of the chief zymotics, from the 

 returns of the Kegistrar-General, under the headings he 

 adopted down to 1868 for to divide fevers into three 

 kinds for half the period, and to separate scarlatina and 

 diphtheria, as first done in 1859, would prevent any use- 

 ful comparison from being made. 



The lowest line, as in the larger diagram, shows small- 

 pox. Above it is measles, which keeps on the whole a 

 very level course, showing, however, the high middle 

 period of the zymotics and two lew periods, from 1869 

 to 1876, and from 1848 to 1856, the first nearly cor- 

 responding to the very high small-pox death-rate from 

 1870 to 1881; and the other just following the two 

 small-pox epidemics of 1844 and 1848, thus supporting 

 the view that it is in process of replacing that disease. 

 Scarlatina and diphtheria show the high rate of zymotics 

 generally from 1848 to 1870, with a large though irregu- 

 lar decline subsequently. Whooping-cough shows a 

 nearly level course to 1882 and then a well-marked de- 

 cline. Fevers (typhus, enteric, and simple) show the 

 usual high middle period, but with an earlier and more 

 continuous decline than any of the other zymotic dis- 

 eases. We thus see that all these diseases exhibit com- 

 mon features though in very different degrees, all 

 indicating the action of general causes, some of which it 

 is by no means difficult to point out. 



In 1845 began the great development of our railway 



