APOCRINE SWEAT IN PRODUCTION OF AXILLARY ODOR 171 tinental Filling. Numerous patents have been granted on valve structures and containers which apply to the aerosol industry. The scarcity of chem- ical composition patents can be ascribed to the fact that the industry only dates back to 1947 and has grown significantly only in the last four years. BIBLIOGRAPHY (1) Beard, Walter C., Jr., "Aerosol Powder Dispensing, Process and Valve Consideration," Proceedings of the Forty-first Annual Meeting of the Chemical Specialties Manufac- turers Assoc., Inc., December 8, 1954. (2) "Aerosol Powders," DuPont Kinetic Technical Memorandum No. 17, October 23, 1954. (3) "Propellents for Low Pressure Cosmetic Aerosols," DuPont Kinetic Technical Memo- randum, December 15, 1954. (4) Johnsen, M. A., "Solubility of Glass Aerosol Compositions," Soap and Chemical Special- ties, 168 (May, 1954). (5) DuPont Kinetic Technical Bulletin B-2. (6) Sandell, E. B., "Colorimetric Determination of Traces of Metals," New York, Intersci- ence Publishers, Inc. (1950) p. 363. (7) Clark, R. E. D., Analyst, 61, 242 (1936): 62, 661 (1937). (8) Farnsworth, M., and Pekola, J., "Determination of Small Amounts of Tin with Dithiol," Anal Chem., 26, 735 (1954). (9) Hoar, T. P., Trans. Faraday Soc., 30, 472 (1934). (10) Mantell, C. L., and King, W. C., Trans. Am. Electrochem. Soc., 52, 435 (1927). (11) Kohman, E. F., and Sanborn, N.H., Ind. Eng. Chem., 20, 1373 (1928). (12) Lueck, R. H., and Blair, H. T., Trans. Am. Electrochem. Soc., 54, 257 (1928). (13) Hamilton, H. W., and Campbell, H. A., "Aerosol Regulations," Soap and Chemical Specialties, 155 (August, 1955). (14) Proceedings of Chemical Specialties Manufacturers Assoc., 40th Mid-Year Meeting, May 25, 1954. THE ROLE OF APOCRINE SWEAT IN THE PRODUCTION OF AXILLARY ODOR* By WALTER, B. SHELLEY, M.D., P•q.D. University of Pennsylvania School of Medicine, Philadelphia, Pa. THE SKIN O•' mammals is commonly provided with special glands which produce odoriferous secretions possibly of great significance. Actu- ally we have but a faint appreciation of the role of these glands, since our mediocre olfactory powers permit us but little perception of much of the world of odors. Nevertheless it is known that these cutaneous scent glands have a protective as well as a sexual role (1, 2). Man himself has probably lost much of his antediluvian mammalian odor yet there are vestigial glands to be found in lesser or greater numbers in certain restricted areas of the skin. These are the apocrine sweat glands. They are found in abundance in the axilla. In the absence of * Presented at the September 15-16, 1955, Seminar, New York City.

172 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS washing, the axilla rapidly acquires a distinctive malodorous scent. This has been viewed as the result of apocrine sweating. For years, society has called for the suppression of this odor of axillary sweat. Cleanliness and the use of perfumes have been eminently successful and, aside from psycho- analytic musings regarding the deep sexual significance and attractiveness of apocrine sweat, little attention has been paid to the problem. Our studies in the field (3, 4) have convinced us that indeed apocrine sweat is the cause of axillary odor. However, this odor is not an intrinsic property of apocrine sweat, but rather it arises from the action of skin bac- teria on the sweat. It is important to review briefly the apocrine sweat gland and its physi- ology before discussing the specific aspect of odor. The apocrine sweat glands are small glandular appendages made up of a secretory reservoir coil deep in the skin and a duct which passes to the skin surface, usually emptying into the upper part of the hair follicle. The sebaceous glands also empty their oily secretion into the hair follicle, at a point just below the apocrine duct. The axilla shows the greatest number of apocrine glands (at least one per hair), but other areas also have apocrine glands (ear canal, genitalia, nipples, umbilicus). It is interesting to point out here that the mammary gland is actually a highly specialized evolutionary development of the elementary apocrine sweat gland. One final note is the fact that this apocrine gland never develops before puberty and that it involutes in old age. The apocrine gland is continuously producing sweat which is stored in the secretory tubules. These tubules are surrounded by a mesh of smooth muscle known as myoepithelium. It is this muscular sheath which con- tracts to neural or mechanical stimuli, forcing the preformed apocrine sweat to the skin surface. Only a tiny drop of liquid appears at any one gland orifice in this process of apocrine sweating. Further secretion is not forthcoming for hours once a gland has been emptied. Apocrine sweating may result from strong emotional stimuli, such as fear, anger and indeed sexual excitement. Apocrine sweating does not occur as a result of high environment temperatures, since the quantity of secretion is insignificant from any thermoregulatory standpoint. Thus, it is the "hot spot" rather than the "hot room" which actuates apocrine sweating. The axilla possesses eccrine sweat glands, as well as the apocrine and sebaceous glands. These are the ordinary sweat glands which give us such valuable evaporative cooling. But in the axilla the eccrine sweat glands respond to both high temperatures and emotional stimuli. Hence the axillary eccrine glands may secrete to the same stimuli as cause expul- sion of apocrine sweat. This eccrine factor was a stumbling block to all early investigators of apocrine sweating. Most of them chose to ignore the presence of this eccrine sweat, simply labeling any fluid secretion from the axilla as apocrine sweat.