PREPRINTS OF THE 1997 ANNUAL SCIENTIFIC MEETING 67 Table 2. Salon test results, for hair softness. [ Attribute [ P Softness 2.3 Shampoo * 3.0 ß Significantly different, better in this attribute. 2) Panel evaluation A double-blind panel evaluation was conducted where treated hair swatches were evaluated by 25 panelists. This subjective evaluation was conducted with a control shampoo (no active, 10% SLES-EO2) (Shampoo L), and a shampoo with 0.3% active Hydroxypropyl Guar Hydroxypropyltrimonium Chloride in this base (Shampoo J). As seen in Figure 2, Shampoo J, with the active material, made hair softer than Shampoo L, showing the contribution of the guar to hair softness. Means and 95.0 Percent LSD Intervals 7.5 7 4 J L Figure 2. Softness panel ratings for Shampoos J and L, showing Shampoo J to be superior. NEW APPROACHES IN EVALUATION OF MOSQUITO REPELLENTS T.S. Spencer, Becwar-Spencer Associates, and W.G. Reifenrath, StrataCog Inc. Personal Repellents applied topically to the skin evaporate to form a vapor barrier above the skin that breaks the seeking-feeding approach of the female mosquito, thereby repelling the mosquito from the skin. Topical mosquito repellents have traditionally been evaluated by application to the skin, followed by exposure to mosquitoes over a peri9d of hours. New approaches in evaluation of novel repellent formulations include in vitro assessment of repel- lent volatility and simultaneous measurement of evaporation and penetration of repellent from skin in vitro using a variation on skin permeation cells. Results from these studies have identi- fied differences in repellency and attractancy among people and also groups of human skin emanations that repel and attract mosquitoes. Several combinations of these naturally occur- ring skin emanations have demonstrated repellency comparable to the most common repellent compound, N,N-diethyl-m-toluamide.