Sulfur dioxide is one of the gaseous products of the combustion of coal and of other industrial operations, sulfur dioxide is discharged into the atmosphere of industrial centers in large quantities. This gasses are predicted exclusive of the discharge of internal combustion engines, the amount of sulfur dioxide released into the atmosphere of New York City during 1934 averaged close to 2000 tons per day. Recent studies by the Air Hygiene Foundation, the National Research Council of Canada, the United States Department of Agriculture, the Boyee Thompson Institutions of sulfur dioxide prevail over large areas surrounding industrial centers. The effect of sulfur dioxide on vegetation and on animal and human health are, therefore, of importance to agriculture, to industry and to the general population. The injurious effects of sulfur dioxide on plants have been the source of investigation, extended litigation, and discussions over a period dating back to the work of Stockhardt in 184...