PURE WATER. 861 



The mortality from epidemic and contagious diseases, both local and' general, 

 has been repeatedly demonstrated to be proportional to the impure condition 

 of the atmosphere of houses or localities. On the other hand, a decrease in 

 the amount and severity of zymotic diseases, and in the rate of mortality in- 

 duced by them, has been shown to follow sanitary improvements in different 

 towns. In the city of Salisbury, the annual average mortality during eight 

 years previous to the complete drainage of the city, was 27 in 1000 ; whilst in 

 the succeeding eight years, in was reduced to 21 in 1000. In the city of Ely, 

 with a population of 6176 persons, living in 1200 houses, the average annual 

 death rate, in the seven years from 1843 to 1849 inclusive, was 26 per 1000 ; 

 in the year 1851, public sanitary works were brought into operation, and, in 

 the seven years from 1851 to 1857, the death rate was reduced to 20^, whilst 

 in the last of those years, it was only 19 in the 1000. Besides securing a larger 

 supply of better water, 4000 cubic yards of cesspools were filled in, and trapped 

 water-closets were substituted ; but, in 1857, 200 houses were yet unconnected 

 with the public drainage, and the pigsties were left, as being too sacred to 

 be touched. It is noticeable, that, whilst the death rate in this city -was re- 

 duced, subsequent to the sanitary improvements, from 26 to 19, the annual 

 death rate in the surrounding country was still 21, in 1857. (William Marshall.) 

 The annual mortality at Pau, one of the healthiest places in France, varies 

 from 28 to 23 per 1000 ; the highest actual mortality in England is 45, the 

 lowest is 11, and the average, 22, per 1000. A comparison with these figures 

 indicates the sanitary position of the city of Ely. The death rate of 11 per 

 1000, is regarded as representing the inevitable annual mortality of this country; 

 the additional deaths beyond that, constitute the preventive mortality, depen- 

 dent almost entirely on zymotic diseases, the ravages of which might be more 

 or less controlled by sanitary improvements. It has been quite recently shown, 

 that one important and unexpected result of public sanitary improvements, is 

 a marked diminution in the number of deaths from phthisis ; this is probably 

 due to the better system of drainage, and to a general elevation of the health 

 of the inhabitants. (Dr. G. Buchanan.) 



A supply of pure water to a town is of immense sanitary as well as econom- 

 ical importance. It facilitates the cleansing and purification of both dwell- 

 ing-houses and streets, and thus assists in the improvement of the air. It 

 substitutes a wholesome beverage, for that contained in unclean tanks or butts, 

 or for the water of surface wells, which from the soakage of filth, from pigsties, 

 stables, or cesspools, is frequently converted into a deleterious, or even directly 

 poisonous, drink. Impure water may act, by slowly introducing into the sys- 

 tem, organic matter undergoing more or less change, and probably, capable of 

 deteriorating directly, or indirectly, the composition of the blood, and thus 

 ultimately lowering the health, and rendering the body more subject to the 

 influence of zymotic agents. At other times, the water may act as the recep- 

 tacle, the nidus, and the vehicle, of such zymotic poisons. The evidence col- 

 lected first by Dr. Snow, in the epidemics of cholera in Lambeth, and after- 

 wards by the Rev. H. Whitehead, in St. James's, Westminster, and by others, 

 at Epping, and elsewhere, concerning the influence of water in intensifying, 

 or probably in communicating cholera, is too strong to be resisted, though it 

 has met \vith but a tardy acceptance. 



The use of water, free, if possible, from organic impurities derived from 

 dwellings, or from other sources, is as essential to good health as pure air. 

 Filtering and depositing beds fairly purify water, on a large scale ; but in 

 private nouses, if any doubt exist as to the character of the drinking-water, 

 special filtration through animal charcoal, or through the magnetic oxide, or 

 the carbide of iron, or if this be too expensive, boiling, and subsequent agita- 

 tion or exposure to a pure air, are desirable precautions. 



In regard to public improvements, sanitary science consists in the perfec- 

 tion of cleanliness of the town, the house, the water, and the atmosphere. The 

 cost of such improvements, and the great question of the utilization of sewage, 

 have also an economical aspect. For the national welfare, it is essential that 

 sanitary work should be done ; but it is not necessary that it should be directly 

 profitable, or even free from cost. 



