ACTION OF ANTI PERSPIRANTS 795 A. b'orrnalin--Pre-sweat samples in the formalin treated areas were characterized by the presence of amorphous intraluminal masses of eosinophilic material plugging the superficial coils of the eccrine duct (Fig. 3). These intraluminal masses were not PAS staining. The derreal and intraepidermal portion of the ducts appeared patent and normal. A good complement of PAS positive (diastase digestible) gly- cogen was contained in the secretory coil. Following the heat stress, biopsies from the same areas showed a marked change in the microscopic picture. Ducts were widely dilated Figure 7. Periductal inflmmnatiom in aluminum salt treated skin alter one hour sweating. The eccrine unit is otherwise normal without ductal dilatation. The "plug- like" appearance of the horny layer is an artifact of sec- tioning. Pre-sweat samples of this skin are without iu- flammation, leading to the conclusion that perspiration pouring into the derntis invites the reaction. (H. & E. X lOO) throughout their entire epidermal course and occasionally deep into the dennis. Intraluminal masses of PAS positive (diastase resistant) mate- rial, not seen in the pre-sweat samples, now were present along the length of the duct (Fig. 6). In the past this material was thought to play a role in the development of sweat retention and miliarial lesions (9), but it is more likely a secondary event due to the superficial obstruction present. Granules of the PAS positive (diastase resistant) substance are normally secreted by the sweat glands (10), and since the material cannot escape onto the skin surface when the duct is blocked it tends to accumulate intraluminally.

796 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS '- •: •-*..: Figure 8. Skin biopsy from area of alu- minum salt induced anhidrosis. Ductal rupture and leakage of sweat within the epidermis produce the acute inflammatory infiltrate. Note that the superficial coils above the lesion are patent, and the duct is not dilated. Clinically these lesions resembled the prickly heat rash (H. & E. X 250) Both the dilatation of the ducts and the appearance of the PAS posi- tive nonglycogen material speak for continuing glandular function in the anhidrotic skin. Further evidence is seen by the disappearance of gly- cogen, the PAS positive diastase digested substance, from the secretory cdls. In contrast to the pre-sweat samples, those specimens taken after the forced sweating show depletion of this material. It is appropriate to comment that both the pre- and post-sweat sam- ples taken from the water treated skin sites were identical in histologic appearance to those obtained from the formalin areas, with but one im- portant exception. No discernible physical plug was present in the hydrated skin which could explain the high level blockage. This is not an unexpected result since poral closure by water is a temporary, func- tional event due to swelling of the horny layer cells at or near the eccrine ostium (11, 12).