ABSTRACT
T HE specific disease-producing organisms present in water are not easily identified. The tech-niques for comprehensive bacteriological examination are complex and time-consuming. Thus, it has been necessary to develop tests that indicate the relative degree of contamination in terms of an easily defined quantity. The most widely used test involves estimation of the number of bacteria of the coliform group, which are always present in fecal wastes and which outnumber disease-producing organisms.
