THE NEW ENGLAND STATES. 29 



desirable to have a thorough inspection made of the source of the 

 water in question. In the case of a spring or well the possibilities 

 of immediate contamination from the surface should be realized. 

 The season of the year, climatic conditions, and similar factors may 

 constitute valuable data in considering the interpretation of results. 

 It is often necessary to pass upon the quality of a water without 

 having a complete history of the product at hand. In such instances 

 one should be more conservative in his views than when the desired 

 inforhiation is available. In cases of this character the merits of 

 the individual water must be considered on the results of the anal- 

 ysis alone. In general, it is believed that all waters intended for 

 drinking purposes which show the presence of B. coli in a majority 

 of the 1 cc samples should be considered as being seriously polluted 

 and unfit for human consumption; but this standard is to be con- 

 sidered in connection with inspection of source of supply when this 

 is possible. 



