86 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The skin contains two kinds of perspirat0ry glands, the eccrine and the apocrine. Eccrine sweat is not of primary significance as a source of odor, as shown by Shelley, Hurley and Nichols (1) such sweat, when collected by capillary attraction does not develop any odor on standing. Only when obtained e.g., by guiding the edge of a test tube with pressure over the skin, does a collected specimen develop odor but its origin resides primarily in certain contaminants, such as keratin and sebum which are being acted upon by bacteria removed from the surface of the skin, at the same time. On the other hand, apocrine sweat itself carries organic material of protein and lipid character, which upon reaching the skin surface is subject to bac- terial attack and decomposition with formation ofmalodor. Since the apo- crine glands are abundant in the axillary area (in association with eccrine glands) the perspiratory odor is particularly noticeable there (incidentally, also in the pubic region, and for the same reason). Both the eccrine and the apocrine varieties of sweat are substantially odorless when collected from a freshly cleaned area. And while the action of skin bacteria gives rise to odor, filtration of mixed perspiration through a Berkefeld assembly (which removes suspended bacteria) prevents a change of the original odor on standing, as shown by Killian and Panzarella (2). For the sake of completeness, it should be mentioned here that children of prepuberal age do not produce apocrine sweat, and do not, therefore, de- velop the characteristic underarm odor. In agreement with this fact is the observation that comparatively little axillary odor is found in the post- climacteric woman. On the other hand, healthy men of an advanced age group (i.e.,past sixty-five) produce axillary odor, but only if they are capable of secreting apocrine sweat. ANTIPERSPIRANTS In formulating one of the several varieties of antiperspirants, the cos- metic chemist usually proceeds upon the premise that he has to employ some astringent chemical in order to produce an inhibition of the flow of perspiration. At one time, he may have explained antiperspirant action by postulating a coagulating effect of the astringent upon some skin proteins which may have been further intensified by the liberation of free acidity in the course of the reaction all this was supposed to cause a swelling around the orifice of the sweat duct, effecting its constriction and thus a reduction of the flow of perspiration. Unfortunately, available dermatological evidence on this subject is quite controversial in character. Shelley and Horvath (3) have shown that pro- longed exposure to a concentrated aluminum chloride solution of an origi- nally profusely sweating skin area causes sweat retention, even to the extent of producing vesiculation but this is an extreme case characterized by the employment of extreme experimental factors. On the other hand, Sulz-

ASPECTS OF ANTIPERSPIRANTS AND DEODORANTS 87 berger, Zak and Herrmann (4) working with aluminum sulfate creams could not demonsu ate histologically a narrowing of the sweat duct or orifice in axillary biopsy specimens. Nevertheless, antiperspirant activity has been observed at the time of biopsy, and attributed to a periductal inflam- matory process. At the same time, the histologically established changes in the apocrine tubules might also be expected to cause a reduction of apo- crine secretion. Incidentally, none of the test subjects exhibited any gross, clinically discernible alteration, irritation or inflammation. But KillJan (5) noted that an antiperspirant cream containing 12 per cent of anhydrous aluminum sulfate was effective in reducing thermally stimulated sweating by as much as 60 per cent on the first day of the test, and by 75 per cent on the second and the following days. For certain valid experimental reasons, two daily applications of the cream were made comparable data obtained in the case of the morning and the• afternoon collections offer strong evi- dence in support of the contention that deodorants based upon aluminum sulfate can effect a significant inhibition of the perspiratory flow. Con- comitantly, a marked reduction of the bacterial counts was obtained follow- ing the first application, and maintained throughout the test period. By contrast, Brun and Manuila (6) find aluminum sulfate (and, incidentally, aluminum acetotartrate) ineffective as perspiration inhibitors aluminum chloride and nitrate, however, produced observable results. Shelley, Hurley and Nichols (1) deny that antiperspirant creams based upon alu- minum salts, are cp.p:tble ofeffecting any significant reduction in the flow of axil]ary perspiration. They .concede that they might produce some degree of anhidrosis on other non flexural body surfaces, such as the back or the abdomen, particularly after repeated application. They explain the virtual absence of such an effect in the axillary area by assuming that the contin- uous eccrine sweating tends to wash away the aluminum salts, thereby pre- venting their reaction with keratin which is essential to poral occulsion and to resultant anhidrosis. Incidentally, a zinc oxide paste was also used in this series of experiments to determine the possibility of mechanical blocking with such a preparation. It was found to be ineffective, however, which is not surprising in view of the fact that apocrine glands secrete against an external pressure of 225 min. of rig, as shown previously by Shelley and Hurley (7). At any rate, Shel- ley, Hurley and Nichols believe that the so-cilled antiperspirant cosmetics act essentially as deodorants, by virtue of two mechanisms: (1) inhibition of bacterial activity, and (2) neutralization of odor by chemical combina- tion with the odorous substance. Which is the last word on the subject, I would not venture to indicate. After all, it is known that because of their polyvalent cation, aluminum salts can act as protein coagulants, and that therefore a reaction with some skin proteins at the ostium of a sweat duct, leading to a reduction of the