Linolic acid (tetrabromides calculated as sudh) is present in human serum to the extent of about 5% of the total fatty acids, and arachidonic acid (polybromides calculated as such) about 37% of the total fatty acids in pooled samples of blood serum from normal children. The content oi both these fatty acids is definitely diminished in children with eczema. In those cases of active eczema which were clinically cured either by the internal administration of oils rich in the unsaturated fatty acids or by the local application of ointments containing crude coal tar, or both, the arachidonic acid was not increased while the linolic content was the same 2s that found in normal subjects. These findings indicate a possible reason for the low iodine number of the serum fatty acids in eczema and further suggest that a disturbance in the metabolism of the unsaturated fatty acids may be one of the many factors at fault in this condition.