Since the so-called patch test (J. Jadassohn; B. Bloch) has been adopted widely for examination of eczema, various authors have suggested modifications of the technic, lately with a view to particular purposes (Rattner1; Guild2). In the dermatologic department of the Finsen Institute, systematic studies have been carried out since the autumn of 1938 on the non-specific (i. e., caustic) effect of various terpenes on the skin. To begin with, the same method was employed as is used in this institute for eczema tests. A strip of boiled linen, an impermeable layer of cellophane and adhesive tape for fixation are used, up to six tests being performed on the same strip. The result is read after twenty-four hours, and a control reading is made on the following days (Bonnevie3). The first examinations gave paradoxic results. For instance, the same concentration of a substance, such as 100 per cent