THE RELATIONS OF BACTERIOLOGY 215 



and is being at least in part carried out. In typhoid fever the evidence 

 from epidemiology has long pointed unmistakably to drinking-water 

 as being the chief vehicle of infection, and the first step toward sup- 

 pression of this disease has been already taken in most civilized 

 countries. The last half of the nineteenth century witnessed an im- 

 provement in the sanitary quality of public water-supplies which has 

 diminished perceptibly the death-rate from typhoid fever .This 

 change has been in part effected by the introduction of water from 

 unpolluted sources, in part by the installation of sand filters. To cite 

 a few well-known cases: For five years before the introduction of a 

 filtered water, the annual typhoid fever death-rate in Zurich, Switzer- 

 land, averaged 76; in the five years following the change it averaged 

 10. In Hamburg, Germany, for a corresponding period before filtra- 

 tion, the typhoid death-rate was 47; after the change it fell to 7. 

 In Lawrence, Massachusetts, under similar conditions the typhoid 

 rate was reduced from 121 to 26, and in Albany, New York, from 104 

 to 38. A similar effect has been noticed where an impure water has 

 been replaced by water from unpolluted sources. In Vienna, Austria, 

 the abandonment of the River Danube as a source of supply in favor 

 of a ground water diminished the typhoid fever death-rate from over 

 100 to about 6. In the United States the city of Lowell not long ago 

 exchanged the polluted water of the Merrimac River for a ground 

 water-supply, with the result that the typhoid fever death-rate was 

 reduced from 97 to 21. In spite of these remarkable facts, there has 

 been a lethargic slowness in profiting by the lessons that they teach. 

 Many communities have remained to this day unobservant and 

 negligent, and especially in the United States, the condition of the 

 average public water-supply demands radical reform. A method that 

 has not only reduced the deaths from typhoid fever by about 75 per 

 cent., but has also reduced the number of cases proportionately, is 

 worthy of universal adoption. If the fatality in all cases of typhoid 

 fever was diminished, say from 12 per 100 cases to 3, by the use of 

 a new drug or an antitoxin, the world would ring with the discovery. 

 The introduction of a pure water-supply has achieved an analogous 

 reduction in the death-rate, and confers further the enormous benefit, 

 of preventing the occurrence of a similar proportion of cases. 1 In 

 the city of Albany, New York, the annual number of deaths from 

 typhoid fever prior to the installation of a filter-plant averaged 89 

 during a ten-year period; in 1902 there were but 18 deaths from this 

 cause, representing a diminution not only of 71 deaths, but of over 

 700 cases. 



Important as is the function of a pure water-supply in preventing 

 typhoid fever, it is now clear that public hygiene cannot stop here. 



1 Jordan, E. O., The Purification of Water Supplies by Slow Sand Filtration, 

 Journal of the American Medical Association, 1903, p. 850. 



