458 The Philippine Journal of Science i»is 



In summary, the waters from the flowing wells show a remark- 

 able high degree of bacterial purity and may be regarded as 

 safe from pollution by pathogenic bacteria. The pumping wells 

 show a much lower degree of bacterial purity, although it is 

 unlikely that any of them were polluted to a dangerous degree 

 at the time of examination. These wells should be examined 

 occasionally — especially during the prevalence of water-borne 

 diseases — since they cannot be regarded as absolutely safe from 

 pollution. 



