676 SUPPLEMENTARY APPENDIX. 



Effect of Sanitation. 



It is said that the decline has, in the main, been due to changes in the' 

 general conditions of life in the different parts of the United Kingdom, 

 apart from the spread of the- practice of vaccination, — amongst other 

 things, to improvement of sanitary conditions. 



It is beyond doubt that an infectious disease like small-pox is, other 

 things being equal, more likely to spread in towns than in country districts, 

 and more likely to spread in crowded town districts than in others not so 

 densely populated ; so that we should expect a lessened proportion of 

 overcrowded dwellings, by diminishing the opportunities for contagion, 

 to check the prevalence of the disease and consequently to render its 

 mortality less. 



Effect of Isolation. 



It has been maintained that the decline in small-pox mortality is- 

 largely due to more frequent and systematic attempts to isolate those 

 sufEering from small-pox. We think an answer to this contention is to be 

 found in the fact that it is only in quite recent years that there has been 

 any systematic practice of isolating small-pox patients, and that it has 

 been confined even then to a very limited number of localities. The 

 fact to which we are about to call attention in greater detail than 

 hitherto, that the decline in the deaths from small-pox is found almost 

 exclusively among those of tender years, appears also to militate against 

 the contention. The risk of contagion is not confined to children. 

 Adults also are subject to it. If a better system of isolation had been 

 a main cause of the reduced mortality, we should have expected to see it 

 operate in the case of adults as well as of children. At the same time 

 we are far from thinking, as will appear when we come to deal with 

 that subject, that the efforts at isolation which have characterised recent 

 years have been without a beneficial effect on small-pox mortality. 



Sanitary Legislation. 



We have already pointed out that on a priori grounds it is reasonable 

 to think that improved sanitary conditions would tend to diminish 

 the fatality of, and so to a corresponding extent the mortality from, 

 small-pox. And there can be no doubt that the period with which 

 we are dealing has been characterised by an improvement of this 

 description. There has been better drainage, a supply of purer water, 

 and in other respects more wholesome conditions have prevailed. 



It may be useful at this point to furnish a brief summary of the 

 principal Sanitary Acts which have been passed relating to the different 

 parts of the United Kingdom. 



In 1848 was passed the first great and comprehensive measure which 

 may be called the groundwork of our sanitary legislation as regards- 

 England. The Public Health Act of 1848 was, however, principally 

 designed for towns and populous places in England and Wales, not 

 including the Metropolis, which was dealt with in Acts passed in the 

 same year. The powers of local government supplied by the Act were 

 generally an extension of those before given by sundry local Acts to 



