164 ELEMENTS OF GENERAL SCIENCE 



has of course percolated a long distance through soil and 

 rock and is very nearly free from bacteria (fig. 82), but such 

 wells must be carefully guarded against the entrance of sur- 

 face water. The lining of the well should be water-tight, and 

 the surface waters should be carefully drained away from the 

 vicinity of the well. A deep well which is protected so that 

 surface water cannot enter is one of the most reliable sources 

 of pure water. What has been said above regarding wells 

 applies also to springs. 



182. Disposal of wastes in rural districts. In many rural 

 districts the disposal of wastes is not given the attention that 

 its importance demands. Too often manure heaps are allowed 

 to become breeding places for flies, human wastes accumulate 

 in cesspools where they are accessible to flies as well as sources 

 of contamination to wells, and the barns and outbuildings are 

 in a condition that is a continual menace to health. It is 

 obviously impracticable to construct sewage-disposal works 

 which will serve an entire rural district as a city is served by 

 its sewer system. It is, however, entirely practicable for each 

 country residence to have its own individual plant for this 

 purpose, and for each family to keep its own surroundings in a 

 sanitary condition. Better sanitary conditions must be secured 

 in the country before it can become as desirable a place of 

 residence as it should be. 



