Patch tests appeal to the medical and to the lay mind and therefore are becoming more and more popular. There is no question but that they have been valuable in determining the causative factor in many cases of contact dermatitis and have helped to solve many of the problems of that group of cutaneous eruptions loosely labeled as "eczema."
They have been of distinct value in industrial dermatology. In this field of medicine with the diagnosis of contact dermatitis established, a carefully taken history denoting exposure to certain chemicals, followed by properly executed patch tests and a characteristic eruption at the test site, should result in a cure of the patient by removing him from the exposure, and should prevent the affliction of others by its removal from the process. However, if it is proved that it is merely a reaction of a hypersensitive individual, and that the work does