In a recent paper1 we reported on the acid number (A.N.) of the ether-soluble substances collected from the skin of patients with psoriasis in comparison with the values obtained in healthy subjects. Collections were made from both the intact skin surface and from the base of the stratum corneum. Access to this deeper level, the "barrier zone," or "stratum conjunctum," of Szakall, was gained by using Scotch cellophane tape to strip away the outer horny layers, i.e., the "stratum disjunctum."2-5 In earlier studies, the acid number of the lipids collected from the barrier zone (B.Z.) in healthy subjects was found to be lower than the acid number of the samples collected from the unstripped skin surface (S.S.). In psoriatic patients, however, there was a quite constant reversal of this relationship; that is, we found the acid number at the barrier zone to be higher than at the skin