THE RATES OF MORTALITY. 73 



which is equivalent to a saving of one life in every 134, or 

 a reduction of O' 1 7 in the general death-rate; but tested 

 by their effect on the whole class of zymotic diseases, they 

 have caused no improvement whatever, and have not even 

 prevented an increase in the mortality from these diseases, 

 which is equivalent to an extra loss of life in every 417. 



(2) Considering the great increase in the fatality of 

 small-pox when that from all other infectious diseases has 

 diminished, that it has now become relatively much more 

 prevalent among adults than at any time since vaccination 

 was introduced, that the experience of the last and of the 

 present epidemic has furnished abundant proof that vacci- 

 nation does not now, as it did in Jenner's time and for 

 many years after, afford an almost certain protection 

 against its attacks, and that the question of the probab i 

 lity of its gradually becoming greatly modified and pro- 

 ducing results that may be seriously unfavourable to the 

 public health has, apparently, never been considered and in- 

 vestigated, it is desirable that an authoritative inquiry into 

 the whole subject should be at at once set on foot, in order 

 to ascertain, if possible, why vaccination has now become 

 so much less efficacious as a preventive of small-pox than it 

 was for many years after its general adoption, what has been 

 the true cause of the great increase of small-pox during the 

 last fifteen to twenty years, and why adults have become 

 so much more liable to its attacks. 



(3) That the reduction in the rate of mortality from the 

 class of infectious or preventible diseases has been more 

 than counterbalanced by an increase in the rate from the 

 non-preventible class ; and that, owing to the changes which 

 have taken place in the latter, the mortality from diseases 

 which run their course rapidly and cause comparatively 

 sudden deaths, has greatly increased. 



