METhODS

The phenomenon with which we are concerned in this paper was discovered incidentally in studies, reported elsewhere (2), of the reparation of facial skin following dermabrasion for removal of acne scars. Dermabrasion was accomplished by Kurtin's technic in which the skin is frozen solidly with refrigerant liquids, and then abraded with wire brushes revolving at high speeds (3). Our observations were confined to five Negro adult subjects, on each of whom a two inch circular facial area was planed to an approximate depth of 2 millimeters. This method does not ordinarily allow a greater depth of removal, which is about half way through the corium of the facial skin. The planed areas were on the cheek where vellus hairs predominate and coarse terminal hairs are sparse. Vellus follicles on the face average about 0.8 millimeters in length with a range of 0.5 to 1.0 millimeter. Biopsies were taken immediately after planing in four of the five individuals and in none of these was there evidence of remnants of any portion of the vellus hair or its follicle. Accordingly, we were satisfied that the technic actually removed vellus follicles completely. We shall acknowledge forth-with, that the classification of human hairs into two polar types, fine vellus and coarse terminal, is somewhat compromised by the existence of intermediate types, which we occasionally encountered; but follicles of this class were excluded from consideration. Biopsies were performed in each of the five subjects two to four times at intervals varying from one week to two months, with a different scheme for each patient.