EFFECTS OF AFTER-SHAVE LOTIONS ON SKIN FLORA 755 evenness of application. After taking the base count, 0.3 ml. of the lotion to be tested was applied to each cheek and allowed to dry for ten minutes. Another set of plates was applied to determine the initial reduction. The subjects •xere now free to go on with their normal routines with the only precaution that they were not allowed to wash their faces during the course of the test. Every two hours new plates were applied for a total of six hours. All plates were incubated for twenty-four hours at 37øC before counts were made. Each solution and lotion tested was run in triplicate on five different subjects. Figure 6 shows a typical series of plates. The initial one is at the Figure 6.--Results of incubation of in vivo inoculated plates. Upper-left--initial upper center--10 minutes after application of lotion upper right--2 hours after application of lotion lower left•4 hours after application of lotion lower right--6 hours after application of lotion. upper left, followed by the ten minute, two hour, four hour and six hour plates. The results are presented graphically on the following slides. Figure 7 shows the results obtained from the seven test solutions. Counts varied among the individuals from approximately 25 to 150/sq. cm. In every case, however, the decrease in skin flora after the application of the lotions was proportional, regardless of the initial count, and recorded in terms of per cent of original count. The four thin lines at the top of the graph represent solutions #1 through #4 containing all after-shave lotion ingredients except perfume. Immediately after application, the counts have been decreased to between 5 and 25% of the initial values Two hours later the counts have risen to between 55 and 75% and after four hours are in the 85o5/o range. At the conclusion of the test at six hours, the skin counts have returned to the subjects' pre-test level. The three lower lines show the effect of adding perfume to the basic ingredients in after-shave lotions. The reduction in skin flora immediately

756 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS after application are only slightly lower than obtained with the solutions but are marked after this point. After two hours, the count had risen to about 25% of the initial reading 100 9O 8O 7O (• 60 o 540-- 3o I 2 3 4 5 Time in hours Figure 7.--Face Plate Counts--Laboratory prepared test solutions. and after four hours to between 40 and 55%. At six hours, the count is about 35% lower than that obtained without perfumes. When a germicide, such as hexachlorophene, is added to the solutions, the results are even more dramatic. Figure 8 shows an almost complete kill of