210 BACTERIOLOGICAL EXAMINATION OF WATER. 



be found after nine days, but in Loch Katrine water it lived 

 for nineteen days, and in the deep well-water for thirty -three days. 

 In the deep well-water the ordinary water bacteria increased far 

 more rapidly than in the Thames and Loch Katrine waters, so 

 Frankland believed that the disappearance of the B. typhosus 

 could not be due to the action of the water-organisms. Klein 

 introduced a recent culture of B. typhosus into unsterilised 

 tap-water derived from the West Middlesex, Kent, and New 

 River companies, and kept the samples at room temperature. 

 Eighteen days after the inoculation living typhoid bacilli were 

 found in O'l c.c. from each of the waters. After thirty-six days 

 typhoid bacilli were not detected in 1 c.c. of the New River and 

 Kent waters, but they were found in the West Middlesex water. 

 After forty-two days the typhoid bacilli appeared to have 

 disappeared from all three waters. In sterilised waters the 

 B. typhosus has usually been found to have a more prolonged 

 existence. Straus and Dubarry found it lived for sixty-nine 

 days in distilled water, for eighty-one days in sterile L'Ourcq 

 water, and for forty-three days in sterile Vanne water. Hoch- 

 stetter, however, stated that the B. typhosus only lived for five 

 days in distilled water and for seven days in sterile Berlin water. 

 Wolff huge! and Riedel, working with sterilised Panke water, 

 found that the B. typhosus multiplied when the temperature 

 was favourable, viz., above 16 C., but when the temperature 

 remained below 8 C. the bacillus remained alive but did not 

 multiply. Klein found the B. typhosus lived for eighty-five 

 days in sterilised water derived from the New River, West 

 Middlesex and Kent companies. 



Numerous experiments have been made on the vitality of the 

 B. typhosus in sewage. Klein found that it could be detected 

 in ordinary sterile sewage three weeks after inoculation. Laws 

 and Andrewes experimented with sewage from Barking and 

 Crossness. At first the sewage was sterilised by boiling, but 

 in the later experiments the sewage was twice filtered through 

 a Berkefeld bougie and then heated to 60 C. in a sterile flask 

 for twenty minutes on two successive days. Planted out in this 

 sewage and incubated at 37 C. the B. typhosus appeared to 

 die within a few days : it could not be recovered after seventy- 

 four hours. Further experiments were made on the same lines, 



