The Longevity of Bacillus Typhosus in Natural Waters and in Sewage.

Abstract

In a paper published in this Journal in 1904,1 Jordan, Russell, and Zeit detailed an extensive series of experiments on the longevity of the typhoid bacillus in water, in which simultaneous, though independent, tests were made on this organism as exposed to the waters of Lake Michigan, the Chicago River, the Chicago Drainage Canal, and the Illinois River. The methods used in this study and the results obtained were so different from those which have previously been reported that it seems desirable to test this question further, employing waters of different origin. The attempt was made in all of this work to approximate, as closely as possible, the conditions that exist in nature, and, for this reason, a marked change in technique was instituted. Heretofore, it has been customary for experiments on the longevity of bacteria to be made in glass containers, filled with sterile or raw waters. The conclusions based on work under these conditions have been shown to be erroneous, and in the work previously referred to, the method was adopted of exposing the typhoid organism in permeable sacs (celloidin and vegetable parchment), filled with the type of water in which the sacs were suspended. If, then, any variation occurred in the composition of the stream in which the sacs were exposed, the influence of such variation, if of any effect, should be felt on the imprisoned cultures within the sac. The results obtained in the experiments conducted on the Chicago Drainage Canal and other waters showed a marked variation in the vitality of B. typhosus. In the relatively pure waters of Lake Michigan, this organism could be recovered readily from the infected sacs, for a period of at least a week, while in the highly polluted waters of