162 



AGRICULTURAL BACTERIOLOGY 



tion of the limestone, which may carry the organisms for 

 considerable distances. The well should not be less than 

 one hundred feet from any possible source of pollution. 



DVJQ WELL. ADEQUATELY PROTECTED 



RGfllNST vSuRTACElCONTWMINAnON 



Fig. 38. Protection of a Well 



All wells should be protected from surface water since this may carry disease- 

 producing organisms 



The chief protection is to be found in the filtering effect 

 of the soil. If no water can enter the well until it has first 

 passed through at least fifteen to twenty feet of soil, there 

 will be little danger of infection. 



There are many ways in which contaminated water may 

 come in contact with milk, as in the case of rinsing the 



