In the United States at present there are five or six establishments which manufacture the bulk of tungsten, molybdenum and tungsten-molybdenum combinations used for electrical contacts and filaments in the great and diversified electrical and radio industries of the nation. In addition to these special plants the large electrical manufacturing concerns have departments which process these metallic products and serve as auxiliary sources of supply. This industry is relatively young and, since the pure metals used in the fabrication of rod and wire are not apparently toxic, it has aroused but little interest from the standpoint of industrial health. However, the processing of tungsten and molybdenum involves the use of metallic mercury and introduces the hazard of exposure to the toxic vapors of that metal.
In order to appreciate the mechanism for development of mercurialism among workmen employed in this industry it is necessary to have some knowledge of metal