6 INTRODUCTION. 



proportion to the improvement of the places it previously 

 infested, in respect to ventilation and cleanliness. Thus, it is 

 BO rare for a case of it now to occur in London, that many 

 practitioners of large experience have never seen the disease. 

 In the Dublin Lying-in Hospital, the number of deaths from 

 it has been reduced to three or four yearly. And there can- 

 not be a reasonable doubt, that, by due attention to the same 

 conditions, it might be exterminated from Iceland and from 

 St. Kilda. There is scarcely, in fact, a disease incident to 

 humanity, which is more completely preventable than this ; 

 and yet the annual sacrifice of life which it formerly caused 

 in our own country alone, might have been reckoned by tens 

 of thousands. 



Although the peculiar susceptibiltty of the constitution of 

 children, gives to foul air and other causes of disease a much 

 more destructive influence over them, than the like causes 

 have over persons more advanced in life, yet it is now well 

 ascertained that the rate of mortality among different classes 

 of the community varies in a degree which bears a very close 

 relation to the nature of the conditions under which they live. 

 Thus, whilst the annual average number of deaths in the whole 

 of England and Wales is about 22 out of every thousand 

 persons living, there are localities in which the annual 

 average exceeds 50 in a thousand, and others in which it falls 

 as low as 1 1 in a thousand. And it is not a little remarkable, 

 that the difference is almost entirely referrible to the mortality 

 produced by Fevers and allied diseases, which, as experience 

 has now fully demonstrated, are absolutely preventible by due 

 attention to the ordinary conditions of health. 



As the population of England and Wales may at present be 

 estimated at about twenty millions, and its actual mortality at 

 about 440,000, what maybe termed its inevitable mortality 

 arising from diseases that would not be directly affected by 

 sanitary improvements would be only one half, or 220,000 ; 

 so that the same number of lives may be considered to be 

 annually sacrificed by the public neglect of the means of pre- 

 serving them, the deaths from typhus alone being no fewer 

 than 50,000. But as it is scarcely to be supposed that every 

 part of our population could be placed in conditions as favour- 

 able as those which prevail where the rate of mortality is 

 the lowest, we may take 13 per thousand as the average to 



