The modern practice of using iced food and drinks is so universal in this country that it is important to determine to what degree ice may be relied on as not carrying infection. When in the seventies and eighties of the last century it was shown that pathogenic bacteria might survive freezing, ice fell under suspicion as a possible medium for the transmission of disease; yet few epidemics have been ascribed to it, and the evidence concerning these has been regarded as inconclusive. H. S. Cumming1 in a recent article makes a study from the point of view of the source of ice, the physical and biologic changes accompanying or consequent on its formation, and the methods employed in its collection or manufacture and handling.
Ice is either natural or artificial. Until recently, in order to secure clean, transparent artificial ice, it was necessary to distil the water used,