128 THE STORY OF THE BACTERIA. 



into the country in the summer, should per- 

 sonally inspect the drinking-water supply and 

 assure himself that it is good. This is actually 

 of far greater importance than the size of the 

 rooms, the price of board, or the diversity of 

 amusements, or any other of the score of 

 things about which one so scrupulously in- 

 quires before laying out the summer cam- 

 paign. 



Wells ought to be cemented water-tight for 

 from eight to twelve feet below the surface. 

 They should rise several inches above the level 

 of the surface of the ground, which should be 

 cemented and made to slope away in all direc- 

 tions from the opening, so that all drippings 

 and surface water may be carried off to a dis- 

 tance of several feet before it soaks into the 

 ground. 



It should always be borne in mind that the 

 water of ordinary wells is simply surface water, 

 which has filtered down through the soil, and 

 collected in the reservoir which the well ex- 

 cavation makes, and that in closely populated 

 regions the soil, which originally may have 

 been efficient as a filter, may finally become so 



