EVALUATION OF ANTIPERSPIRANT ACTIVITY 759 Figure 9. Temperature controller EXPERIMENTAL PROCEDURE The block diagram in Fig. 4 illustrates the test equipment assembled for this procedure. All gas connections are of 3.2 mm Teflon tubing to minimize the permeation of moisture through the walls of these connec- tions. The gas supply system is shown in Fig. 5. Dry nitrogen from the cylinder flows through a sensitive regulator to reduce the pressure to approximately 1000-1500 ram. The wet and dry gas values may be balanced against each other to adjust the delivery of moisture to the main gas stream and to calibrate the operation of the system. The manometer need not be accurate. It is used only to insure that the pressure from test to test remains the same or as a cue to a leaking cup. The mixing chamber assures the thorough distribution of added moisture before the gas stream is diverted to the rest of the system. Clear plastic is used in fabricating the absorption cups (Fig. 6). The importance of relocating them precisely in the identical area for a test

760 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figsire 10. Moisture monitor assembly series requires sufficient visibility for locating placement marks exactly. Note the concentric sections. Dry air in the center one sweeps away the moisture for measurement while a vacuum in the outer section holds the cup in place. A vacuum of more than 130 mm should never be used, as this may injure the subject. Preferably it should remain between 50-75 The cups are placed into the shaved axillae of the subject after he has been rolled into the heating chamber (Fig. 7) and is comfortable on his back. The gas stream is turned on at about 1200 cc per minute, and the whole system is allowed to dry down. The subject should not be perspir- ing at this point. The heating chamber (Fig. 8) consists essentially of a large inverted box on legs into which a subject, lying on his back, may be rolled. His holding the trapeze-like accessory both positions and limits the motion of his arms which may disturb the cups. With the side doors closed the temperature is raised by a circulating hot air blower and controlled by an electronic temperature sensing device. A clear plastic plate (6 ram) has been used throughout its construction to forestall claustrophobic tend- encies of the subjects by allowing them to see out on all sides.