DEATH-TOLL OF ENGLAND AND WALES. 129 



required to contain the full cycle observed by some of 

 thenij as may be seen from the diagram showing the vari- 

 ations in the prevalence of scarlet fever in Sweden. 



The cycle usually followed by small-pox, however, is 

 shorter than this ; and from the exemption of children 

 from the excessive death-rate by this disease it would 

 seem that the protection afforded by infantile vaccination 

 endures now for a shorter period than it formerly did. 



This surmise is in accordance with the facts recorded by 

 Mr. Simon respecting the increase in the number of cases 

 of successful revaccination in the Prussian army during 

 the years 1813 to 1833. 



It points to some imperfection in the operation, or to a 

 possible deterioration in the quality of the lymph, owing 

 to its transmission too constantly through the human sub- 

 ject. In any case, its cause is worthy of full and patient 

 investigation. 



The objections that I have ventured to bring against the 

 details of Mr. BaxendelFs tables also do not apply to his 

 comparison of the gross mortalities of the two periods he 

 has chosen. 



The almost stationary condition of the death-rate of the 

 country during the last thirty years has been noticed by 

 many who are interested in the public health, and who 

 have been disappointed at not obtaining from the Registrar- 

 GeneraFs tables of total mortality that proof they so much 

 desired of the efl&cacy of their sanitary improvements. 

 Mr. Baxendell, indeed, shows that all the zymotic class 

 of diseases, with the single exception of small-pox, have 

 somewhat diminished ; and by limiting the term " preven- 

 tible " to this class of disorders he is able to ascribe to 

 sanitary measures the modicum of improvement repre- 

 sented by " a saving of one life in every 1 34," or " a re- 

 duction of 0*17 per cent, in the general death-rate." 



SER. III. VOL. VI. K 



