114 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS data obtained with the five subjects involved in this test series are shown in Table 2. These values represent the average of 10 to 20 readings, as indicated. It is interesting to note that the lower test site (farthest from elbow) consistently gave the higher readings. T.•Bx.E 3--MoIsTUV. E Loss fRoM Ar)J.•CE•T SITES OF THE I•ER PORTIO• or ThE FORE.•RM (SUBJECT CK), I• .• Two-Hour. TEST PERIOr) Moisture Loss, mg. Upper Lower Date Time R.H. T., øC. Arm Arm Do, %* 6/9 a.m. 55 30 9.2 6/6 p.m. 52 24 11.9 6/10 p.m. 68 26 8.9 6/11 a.m. 65 27 6.9 6/12 p.m. 60 25 8.0 6/17 a.m. 55 24 6.3 6/19 p.m. 57 23 8.9 6/24 p.m. 58 23 10.7 6/26 p.m. 59 26.5 15.4 7/7 a.m. 55 26 11.8 7/8 p.m. 60 25 25.5 7/9 , a.m. 62 24 7.7 7/14 p.m. 69 22 14.1 7/16 p.m. 69 22 12.6 7/17 a.m. 65 22 8.5 7/21 p.m. 62 22 11.5 7/23 a.m. 68 21 9.1 9.7 5.4 12.3 3.4 10.6 19 1 8.5 23 2 8.8 10 0 8.8 39 7 13.0 46 0 13.5 26 2 16.4 6 5 14.4 22 0 33.0 29.4 9.4 22.1 14.1 0 17.3 37.3 9.5 10.8 11.7 1.7 9.4 3.2 AT. Do = 18.0 * Dc = Percentage difference in moisture loss between the L-U D•- X 100 U upper and lower sites. In Table 3 data are shown for the individual readings obtained with a representative subject. Twenty-one cosmetic creams and lotions manufactured by leading companies were then tested for their ability to retard the moisture loss from the skin. A three-quarter gram portion of the test cream or lotion was rubbed into the lower, inner portion of the forearm. The test product was allowed to dry on the skin for fifteen minutes at room temperature and the application repeated followed by a thirty minute drying period. A desiccator was then placed over the test site and a control desiccator was placed directly above and adjacent to it on the untreated portion of the arm. Moisture pick-up readings were taken after the desiccators had been in place for two hours. Ten determinations were made for each product. By calculating the percentage difference in moisture loss between the treated and untreated areas and applying the calibration factor for the subject involved, one can calculate the effect of the test product on moisture loss. The results obtained are presented in Table 4.

EFFECT OF COSMETIC EMULSIONS ON STRATUM CORNEUM 115 DISCUSSION It is interesting to note that of the preparations tested, cold cream E retarded moisture loss to the greatest degree (-27 per cent), while hand cream C, with a high humectant content, accelerated moisture loss to the greatest degree (56 per cent). Eleven of the twenty-one products tested accelerated moisture loss to an appreciable degree (over 5 per cent). Four products had very little effect on moisture loss and only six emulsions retarded moisture loss to any extent. Thus, of these 21 emulsions sold to the public as skin softening preparations, only six could be expected to lead to an increase in moisture content of the stratum corneum with attendant increase in softness and flexibility. TABLE 4--THE EFFECT OF COSMETIC EMULSIONS ON MOISTURE Loss FROM THE SKIN Average Moisture Loss * Sub- Upper Lower Product ject Arm Arm D, % D•, % Net Effect Nutritive cream A CF 12.2 13.8 13 17 4% reduction Moisturizing lotion B GB 16.2 20.7 28 25 3% increase Hand cream C CF 6.7 11.6 73 17 56% increase Foundation lotion D FM 8.2 9.7 18.5 26 7.5% reduction Cold cream E CK 10.3 9.4 -9 18 27% reduction Night cream F GB 22.3 31.3 40 25 15% increase Night cream G FM 24.4 26.9 10 26 16% reduction Night cream H GB 23.8 34.0 43 25 18% increase Moisturizing lotion I CK 13.1 14.7 12 18 6% reduction Night cream J CF 26.2 27.4 5 17 12% reduction Moisturizing gel K CF 15.4 20.1 30 17 13% increase Night cream L CK 11.2 13.9 24 18 6% increase Night cream M LF 9.7 11.8 22 17 5% increase Hand cream N CF 11.0 14.9 35 17 18% increase Hand lotion O CK 7.2 10.5 46 18 28% increase Lubricating lotion P LF 10.4 13.2 27 17 10% increase Hand lotion Q FM 8.7 11.6 34 26 8% increase Hand lotion R FM 11.3 15.9 41 26 15% increase Hand lotion S CF 13.8 17.7 28 17 11% increase Moisturizing lotion T CK 9.5 9.5 0 18 18% reduction Moisturizing lotion U FM 6.7 8.2 22 26 4% reduction * Average of 10 readings. It is also of interest to note that six hand preparations--which are expressly sold to soften the skin--all accelerate the rate at which moisture is lost to the atmosphere. Previous work has shown that many of the nonwater-soluble oils used in cosmetic emulsions reduce the rate of moisture loss from the skin. The present study illustrates, however, how the beneficial effects of an oil as regards its ability to regulate moisture loss can be negated by the addition of emulsifiers and humectants. Further work is needed to study the results of different ratios of the