ANTIPERSPIRANT ACTION OF ALUMINUM SALTS 115 Figures 3a and 3b are a representative example of an ACH-treated sweat gland duct, approximately 20/xm from the skin surface. The duct contained an electron dense, amorphous occlusive mass. In vivo the mass most likely completely filled the lumen. The clear spaces are believed to be artifact caused by either the difficulty in sectioning at this superficial level or shrinkage during tissue preparation. In marked contrast to the lumen-filled ducts of the ten treated glands which were studied, the control sweat gland ducts, an example of which is portrayed in Figure 4, were always patent and devoid of any amorphous mass. Using the morin fluorescence procedure, the occlusive masses found in ACH-treated glands were demonstrated to contain aluminum. Figures 5a-5f represent a serial f - . . / ,.. . ., ,' ' " - ' .• -•,'•,..'" •',,• -' '• ' '--'""-..• ., . %5?. t?. • '-o• • .. , •. f i Figure 3•. Higher magnification of Figure 3a.

116 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS .., •.'• .-•- •. ,I- , .., ':: :::: .'-5," - .... ... :5 Figure 4. Water-treated eccrine sweat gl•d duct at the level of the stratum corneum (L:lumen). sectioning, perpendicular to the skin surface, through the same sweat gland. For this particular gland (one of 12-15 examined in detail), which clearly shows the classic spiraling of the sweat gland duct as it passes through the stratum corneum, the aluminum was present only in the stratum corneum layer of skin. In all glands, the aluminum fluorescence appeared to be a continuum, usually filling the entire diameter of the duct. In those instances where gaps did appear, they may represent tissue sectioning artifact or washout of the material. It was further observed that where the sweat gland duct opened to the skin surface (Figure 5f) a substantial amount of fluorescence was present as if sealing off the pore. In Figure 5f, the greenish tinge in the epidermis is non-specific background fluorescence from protein. The aluminum fluorescence in this photomicrograph,