1955 SEMINAR DISCUSSION 275 charge of a large dermatological clinic in one of the city hospitals. They prefer to use an aqueous solution of 15 per cent aluminum chloride and of a wetting agent, buffered to a pH between 3.0 and 3.5 in cases of hyperhidrosis and osmidrosis, and definitely stated that this solution greatly reduces the secretion of sweat. On the other hand, they did not observe a signifi- cant antibacterial action of the aluminum chloride. This would be in contrast to the findings of Shelley and others. We have not heard much about techniques for determining whether a material, for instance a soap, has an effect on body odor. Probably, the reason is that we lack good reproducible methods, and often suitable test subjects with sufficiently disagreeable odor. We also must consider that as much as the odor of the skin that of clothing having absorbed the sweat would be objectionable. In some of our experimental studies, the test subjects have worn T-shirts and two different soaps were used for washing the skin over a period of time, one in the right and the other one in the left axilla. The difference of odors determined daily on the shirts after having been worn for twenty-four hours was considered to be a criterion of the superiority of one soap as a body deodorant over the other. This difference is quite marked if we compare ordinary soap with a soap which contains an antibacterial agent, e.g., 2 per cent hexachlorophene, and therefore, it is fairly easy to show that an anti- septic soap has better deodorant properties than a plain soap. But if one has two soaps, each one with an antibacterial substance of similar skin- degerming activity, then it becomes quite difficult to establish whether the first soap is significantly more effective as a deodorant than the second one. What we need are more accurate methods for close comparison of body deodorants. KIMIO IKAI, M.D. (Dept. of Dermatology, University of Pennsylvania, Philadelphia 4, Pa.) The lower fatty acids were adsorbed and deodorized by anion exchange resins. Ammonia was adsorbed and deodorized with cation exchange resins, and indole by cation or anion exchangers. Odor of feces was removed by anion exchangers, but more completely by mixtures of cation and anion exchangers. Odor from the secretions of the axillae was adsorbed well by any ex- changers, but here too, the mixtures of cation and artion exchangers were more powerful. Powders and oily or liquid preparations containing mixtures of cation and artion exchangers, when applied to osmidrotic subjects, showed good deodorizing power.

276 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS It may be presumed that fatty acids are adsorbed to anion exchangers, ammonia to cation exchangers and indole to either of these two. That this assumption holds was shown by the experiments mentioned. In human secretions there may be many other substances producing odor. But the experiments with feces, etc., indicate that such substances, if there are any at all, can be taken up by adsorption and turned scentless when ion ex- changers are correctly used. Effective ion exchange resins may successfully be used for the abolish- ment of osmidrotic odor. For manufacturing preparations of practical use, nonionic substances with high surface activity are suitable to use as vehicles. In recent experiments observing the activity of cation exchange resins mixed with various bases, Jurist concluded that hydrophile or water soluble vehicles are superior to petrolatum base in rapidity of ion exchang- ing. Though this is confirmed by the results of the experiments on sub- jects above mentioned, it is also regarded that petrolatum, a hydrophobic base, is helpful to lengthen the adhesion'to the skin. The mechanism of deodorant action of ion exchangers may be interpreted as follows: (1) Purified ion exchange resins are not soluble in water and have no astringent action as is the case with aluminum salts. Prevention of sweat secretion is therefore not the cause for deodorization of the ion exchangers. (2) It has recently been demonstrated by Shelley, Hurley and Nichols that human apocrine sweat is odorless and sterile when it initially appears on the skin surface and that its acrid odor is only developed by the action of micro•Srganisms. They have also succeeded to prevent odor from development on the axilla for more than eighteen hours by mechanical cleansing and washing with antiseptics. There are several reports con- cerning the antiseptic and bacteria-adsorbing actions of ion exchange resins. One may therefore imagine that the deodorant effect of the ion exchangers is partly due to its germicidal action. In the experiments of Shelly, et al., however, it has been demonstrated that the antiodorant effect of antiseptics is decidedly less in vivo compared with the in vitro experiments, even when they used highly active antiseptics. It seems therefore plausible to conclude that deodorization by the antiseptic action of ion exchangers is little if there is any at all. (3) According to Thurmon and Ottenstein, pH of sweat over the skin may be kept normal for a long time when ion exchangers are used. The growth of bacteria over the skin may be promoted by changes in pH of the sweat and it may therefore be thought that deodorization by ion exchangers is helped by their action keeping pH normal. But from the above consider- ation with regard to the antiseptic action, it seems certain that this mecha- nism is of little significance. (4) From the above account, it may be concluded that the deodorant