While it is generally conceded that, under ordinary circumstances, typhoid fever is most commonly transmitted by water, our knowledge of the life history of the germ in this medium is far from complete. So far as ice is concerned, the matter of the viability of the germ has been pretty well tested, and it is now generally conceded that, except under very unusual circumstances, the danger from this source is practically nil. It has generally been assumed that in water under normal circumstances the bacillus of typhoid fever disappears rather rapidly, partly as the result of physical agencies like light and sedimentation, and partly as the result of the antagonism of the saprophytes with which it is associated. This is, no doubt, partly true, but the recent work of Wheeler1 shows that it is not entirely true. For example, Wheeler found that in well water with considerable organic pollution,