CHAP. xvm. VACCINATION A DELUSION. 253 



account for the lesser declines in zymotic diseases and in 

 small-pox, both of which began in the last century, and 

 only became somewhat intensified in the first quarter of 

 the present century, to be followed, twenty years later, 

 by a complete check or even a partial rise. This rise 

 was equally marked in small-pox as in the other diseases, 

 and thus proved, as clearly as anything can be proved, 

 that its decline and fluctuations are in no way depend- 

 ent on vaccination, but are, due to causes of the very 

 same general nature as in the case of other diseases. 



To give the evidence for this improvement in London 

 hygiene would, however, break the continuity of the 

 discussion as to small-pox and vaccination; but the com- 

 parison of the general and zymotic death-rates with that 

 of small-pox exhibits so clearly the identity of the causes 

 which have acted upon them all as to render the detailed 

 examination of the various improved conditions that led 

 to the diminished mortality unnecessary. The diagram 

 showing the death-rates from these three causes of itself 

 furnishes a complete refutation of the Commissioners' 

 argument. The evidence as to the nature of the im- 

 proved conditions is given in an appendix at the end of 

 this chapter. 



Small-pox and other Diseases in Britain during the 

 Period of Registration. 



We have no general statistics of mortality in England 

 and Wales till the establishment of the Kegistration sys- 

 tem in 1838, but the results make up for their limited 

 duration by their superior accuracy. Till the year 1870 

 no record was kept of the amount of vaccination, except 



