278 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (4) With reference to the electrical potential difference between the proximal and the open end of the eccrine gland duct, is it not possible that the cation of any metal salt would have the same effect as the cationic quaternary ammonium compounds ? A cationic compound of the type of benzalkonium chloride has specific surface activity, and its electropositive character tends to neutralize the electro-negative charge at the ostium, thereby counteracting the tendency of the positively charged sweat to flow outward. It was pointed out that an effect similar to that of benzalkonium chloride can be produced by solu- tions of certain electrolytes from the positive end of the Hofmeister series, such as lithium iodide at the same time, other iodides are less effective. Thus, not all cations should be regarded as being equivalent to a cationic surfactant in this respect. Another point to be considered, is the antagonizing effect of the anion in other words, with a given cation, the sulfate may do one thing while the thiocyanate may do another. As to the comments made by Mr. Fredell and Dr. Herrmann, I am glad to note their observation to the effect that aluminum salt based antiperspirants in cream vehicles prepared with anionic emulsifiers showed, initially at least, a pro- vocative rather than a suppressive effect upon the flow of perspiration, but that no such effect was obtained with aqueous solutions. All this fits in with the postulate as to the existence of an electrophysiologic potential along the sweat duct. FRANZ HERRMANN, M.D. (New York University Post-Graduate Medical School, New York, N.Y.) To question of sebum as a possible source of the odorous fatty acids: As Ikai has indicated, it was he and Nitta [Nagoya Med. y., 1, 217 (1953)] who by means of paper chromatography demonstrated a preponder- ance of unsaturated fatty acids with four to ten carbon atoms in sweat from osmidrotic axillae, in osmidrotic cerumen, and in osmidrotic smegma, whereas fatty acids with less than four carbons prevailed in the specimens from nonodorous axillae. (There was quite a series of subjects with osmidrosis in Japan, after all.) Although lipids are known to be excreted in the apocrine sweat, I think that also other skin lipids, such as those sup- plied by the sebaceous glands, may well be a source of the pertinent fatty acids. At this, the apocrine sweat may be effective by emulsifying sebum with special avidity and by furnishing a medium favorable for the growth of certain micro6rganisms. To Klarmann's remark on chlorophyllin and asparagus odor of urine: Kanof and I (New York University Skin and Cancer Unit) carried out trials with chlorophyllin given by mouth, or added to the urine, after inges-

1955 SEMINAR DISCUSSION 279 tion of asparagus no change whatever of the characteristic odor was noticeable. To Conrad's questions: While the surface lipids of normal human skin contain about 5 to 10 per cent squalene, there are characteristic species differences in wool fat, for example, squalene being absent or occurring only in traces (Sobel, Mac- Kenna, Wheatley and Wormall Rothman and Nicolaides). The species differences resemble those which exist in the fatty acid contents of skin fat from different species. Squalene is a physiologic precursor of cholesterol. The squalene content of human hair fat shows a three- to fourfold increase after puberty, whereas the cholesterol concentration declines by just as much (Rothman and Nicolaides). Considerably more cholesterol is pres- ent in the lipids on the stratum corneum than in "native" sebum. It appears possible that the conversion of squalene into cholesterol indirectly promotes the formation of the unsaturated fatty acids largely responsible for "body odor." To Lyon's remark: In support of Lyon, I should on this occasion re-emphasize the great shortcoming which obviates a satisfactory answer to the present question and to many other questions in this field, in that we are practically unable to obtain pure specimens from each of the different potential sources' of the materials in question. As yet, we cannot insert a catheter into the duct of a sebacesus gland and despite the solitary report by Japanese investigators of successful catheterization of an eccrine sweat duct, we generally are still unable to collect the unadulterated products of any of the skin glands. Many tedious attempts on our part (New York Skin and Cancer Unit) have failed thus far. Moreover, I cannot conceive of apocrine sweat being collected in a capillary placed into a hair follicle or directly on the skin sur- face without any admixture of sebaceous matter. Present knowledge indicates that most of the fatty acids encountered on the skin surface are not of glandular origin but formed externally by enzymatic action of the microbial flora. To Malkinson's question: As was aptly demonstrated by Marchionini and Cerrutti [Arch. Der- mato/u. Syphilis, 166, 354 (1932)], osmidrosis or "bromidrosis" of the feet essentially results from impaired evaporation and stagnation of eccrine sweat, with consequent swelling, bacterial infection and decomposition of keratin. The pH of the affected skin surface shows a shift toward alkalin- ity which in turn further enhances the growth of micro6rganisms. The odorous substances apparently are derived from the hydrated keratin by enzymatic action of the microbial flora. Although proper hygiene is useful also in bromhidrosis of the feet, often repeated washings may be less expedient than in the axillae because keratin swelling is promoted.