Water Supply and Sewage Disposal. 215 



lessness often prevails in the matter of disposal of house- 

 hold sewage, the water supply becomes contaminated. 

 The sewage of a city may be discharged into a river, from 

 which another city a few miles further down draws its 

 water for household use. A city may discharge its sew- 

 age into a lake and from the same source draw its water 

 supply, as is the case with nearly all the cities on the 

 Great Lakes. Under such conditions more or less of the 

 sewage is certain to enter the water mains. As stated in 

 the discussion on the relation of milk to transmissible dis- 

 eases, there are people who have recovered from typhoid 

 fever and who continue to harbor in and give off from 

 their bodies the disease-producing organisms. These 

 people are supposed to be the means by which the disease 

 maintains its presence in the community, no matter how 

 much care may be used in the disinfection of the dis- 

 charges of persons known to be suffering from typhoid 

 fever. Cities now realize that it is economy for them to- 

 protect themselves by securing their water supply from 

 sources known to be free from pollution with sewage, or 

 through purification by the proper filtration of water 

 from suspected sources. 



The farm home should likewise be insured against ty- 

 phoid fever through the protection of its water supply 

 from sewage pollution. It is frequently thought that 

 typhoid fever is an urban disease, but as a matter of fact 

 it is more prevalent in the country. The city home is ex- 

 posed to infection by means of the water from many other 

 homes in which typhoid may be present, while the farm 

 home is not related in so direct a manner with other 

 places in which the disease may be present. There, are, 

 however, abundant ways in which the disease may be 

 brought on to the farm. 



