178 Elements of Water Bacteriology. 



be cleaned, and that the workmen in resinking them had 

 used the water of the brook for washing them down. 

 This allowed some of the brook-water to enter the system. 

 It was also found that at the same time the water in the 

 brook had been high, and because of the lack of packing 

 in certain joints at the top of the wells the brook-water 

 leaked into the suction main. The remedy was obvious 

 and was immediately applied, after which the tests for 

 Bacillus coli once more became negative. During all 

 this time the chemical analysis of the water was not suffi- 

 ciently abnormal to attract attention. On another occa- 

 sion a water-supply taken from a small pond fed by 

 springs, and which was practically a large open well, 

 began to give positive tests for Bacillus coli, and on exami- 

 nation it was found that a gate which kept out the water 

 of a brook which had been formerly connected with the 

 pond was open at the bottom, although it was supposed 

 to have been shut, thus admitting a contaminated sur- 

 face-water to the supply." Whipple also calls attention 

 to the report on the Chemical and Bacteriological Exami- 

 nation of Chichester Well-waters by Houston (Houston, 

 1901), in which the results of chemical and bacteriologi- 

 cal examinations of thirty wells were compared. It was 

 foimd that the bacteriological results were in general 

 concordant and satisfactory. The wells which were high- 

 est in the number of bacteria showed also the greatest 

 amount of pollution, as indicated by the numbers of B. 

 coli', B. sporogenes, and streptococci. On the other hand, 



