A Comparative Study of Colon Bacilli Isolated from Horse, Cow, and Man

Abstract

In the routine analysis of water, to determine its potability, the presence of B. coli in 1 c.c. is taken as an index of pollution. The real danger from a polluted or infected water supply is typhoid fever. The colon bacillus is easily determined if present. The determination of the typhoid bacillus is much more difficult. The typhoid organism is never present in a fecally polluted stream or source of water supply without the colon organism's accompanying it. If the colon bacillus is present, the typhoid bacillus is likely to be present also. It is for this reason that the presence of B. coli is taken as an index of pollution in determining the potability of water. The colon organism occurs in the intestines of all warm-blooded animals, and is always present in their excrement. Up to the present time, the colon bacilli in the different animals have not been shown to exhibit any marked or distinguishing features. If some feature or features peculiar to the colon bacilli of one animal could be discovered, it might be of material value in water analysis, as indicating the source of fecal pollution. Acid-forming streptococci, which are also an index of pollution, have been shown by Winslow and Palmer1 to exhibit marked differences in their ability to ferment carbohydrates. A summary of this work is given in the following table.