“…The present position is well summarized by Professor Maxey (1949), who states: "While further carefully controlled studies are desirable, on the basis of experimental results now available, it appears to the author that the application of chlorine under conditions which will insure the maintenance of 0.2-0.3 p.p.m. free available chlorine residuals after onehalf hour of contact may be sufficient to inactivate the quantities of poliomyelitis virus that might be present in a potable water.…”