398 PRACTICAL HYGIENE 



marsh or swamp and, if so near as that, it ought to be on 

 the side from which the wind usually blows. A stone 

 foundation should be provided, and at least eighteen 

 inches of ventilated air space should be left between the 

 ground and the floor. Ample provisions must be made 

 for pure air and sunlight in all the rooms. The cellar, if 

 one is desired, needs to be constructed with special care. 

 It should be perfectly dry and provided with windows for 

 light and ventilation. Adequate means must also be pro- 

 vided, by sewage pipes and other methods, for the disposal 

 of all waste. Where drainage pipes are provided, care must 

 be taken to prevent the entrance of sewer gas into the house 

 and also the passage of material from these pipes into the 

 water supply. The placing and connecting of sewer pipes 

 should, of course, be under the direction of a plumber. 



The Water Supply. Since water readily takes up and 

 holds the impurities with which it comes in contact, it 

 should be exposed as little as possible in the process of 

 collecting. Where cistern water is 

 used, care must be taken to prevent 

 filth from the roof (Fig. 168), water 

 pipes, or soil from getting into the 

 reservoir. Water should be collected 

 from the roof only after it has rained 

 long enough for the roof and pipes 

 to have been thoroughly cleaned. 

 FIG. i68.-Contamina- The dstern should have no leaks 

 tion of cistern water by , 

 birds nesting in the gutter ( Fl &- l6 9>' and the tO P sh uld be 



trough. tightly closed to prevent the entrance 



of small animals and rubbish. 



Shallow wells are to be condemned, as a rule, because of 

 the likelihood of surface drainage (Fig. 169), and water 

 from springs should, for the same reason, be used with 



