DAIRY INSPECTION 193 



not be permitted to fall on the floor or into the bedding 

 when they become detached from the teats. 



4. Water Supply. It is not only important that 

 the water used on a dairy farm for washing the milk 

 utensils and vessels shall be free from fecal contamina- 

 tion, but also that the surroundings of the source of 

 supply are such that there is no probability of contami- 

 nation. While the first point can be decided by a bac- 

 teriological examination of a sample of the water, the 

 second can only be determined by an inspection of the 

 water supply and its surroundings. Frequently inspec- 

 tion will furnish all the information required to condemn 

 a polluted water supply, but in many instances a bac- 

 teriological examination will be necessary. The exami- 

 nations reported of farm water supplies indicate that 

 they are frequently contaminated. 



On many farms the water supply is obtained from 

 springs or from dug wells. In either case, the source 

 of supply is the underground water. A well is an arti- 

 ficial opening from the surface down to the underground 

 water, while a spring is a place where the underground 

 water has come to the surface. The underground water 

 is contained in the interstices between rocks, gravel, sand, 

 clay, etc., at various depths below the surface of the 

 ground. The level of the underground water, i.e., the 

 water table, conforms in a general way to the level of 

 the ground surface (Fig. 22). 



The purity of spring water depends very largely 

 upon the location of the spring. When springs on farms 

 are contaminated, it is usually due to pollution by sur- 

 face wash or subsurface drainage. A dry closet situated 

 on the slope of a hill above a spring is especially dan- 

 gerous. The location of manure piles, houses, barns, pig 



13 



