With regard to the principal purpose of this investigation, it is apparent that exposure to mercury during the preparation of silver amalgam definitely presents an additional occupational hazard as an allergen in the dentist. The fact that the dental students who were the volunteers in this study received only a small fraction of the exposure to mercury that the practicing dentist receives does emphasize the potential of this allergen in actual dental practice. Recent publicity concerning the toxioogenicity of mercury has led to a call for improved mercury hygiene in the dental operatory. The allergenic potential of mercury, as reported in this paper, accentuates the need for such an improvement.