632 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Treat•rzent -period D: (13 days). The treatment for both sides was the same. It consisted of the application of a mixture of suspensions of scurf bacteria and .P. ovale. Method of Removing Scurf Samples Scurf was removed from the scalp with the aid of the Oster HairVac Model 215.* It is supplied with disposable plastic heads which can be sterilized by chemical means. Samples were obtained by passing the apparatus over each half of the scalp 12 times in such a manner as to obtain a uniform collection each time. Three passes through the scalp were made beginning at the right (or left) of the median line and pro- ceeding from temple to nape of neck. Each pass covered a different area of the scalp moving to the right (or left), with the final pass just grazing the top of the ear. The entire procedure was repeated four times for each half. Each subject was permitted to collect his own scurf. Samples were prepared for microbiological examination under sterile conditions. Treatment of Scurf Samples The weights of all samples were recorded. Smears were made, stained with Loeffier's methylene blue and examined microscopically for the presence of _P. ovale and other yeast forms. An evaluation of each sample was made on the basis of the average number of yeast cells counted in 10 immersion oil objective fields. The effect of nystatin in suppressing the numbers of .P. ovale could thus be determined. Bac- terial plate counts were made using Trypticase Soy agar (B.B.L.). The weighed scurf samples were placed in flasks containing 100 ml of sterile saline. After shaking for 10 minutes, 1 ml aliquot portions were plated out. Bacteria counts were computed as number of organisms per mg of scurf sample. RESULTS Scurf Evaluation. Table I shows the average scurf sample weights for all subjects in each sampling period. Except for two subjects (3 and 5) the weights from opposite sides of the scalp during the pre-treat- ment period were very similar. The average weight from eight subjects was 33.7 mg from the left side and 34.5 from the right, a variation of only 2.3%. Subjects 3 and 5 both parted their hair on the left side, * John Oster Manufacturing Co., Milwaukee, Wis.

FLORA OF THE SCALP AND DANDRUFF PRODUCTION 633 Table I The Average Weights of Scurf Sainples for All Subjects in Mg Pre-treatment Treatment Treatment Treatment Treatment Subject Pcriod Pcriod A Period B Period C Period D 1 67.9 2 35.0 3 40.8 4 20.2 5 32.0 6 39.1 7 47.2 8 26.0 9 25.3 10 76.3 Ave. 41.0 77 37 37 19 0 49 0 48 8 55.4 30.3 43.5 56.4 45.4 1 71.4 21.6 2 32.4 24.9 3 62.4 30.6 4 19.5 19.7 5 46.8 48.8 6 43.0 31.9 7 51.8 44.6 8 25.8 32.1 9 29.7 33.4 10 71.7 35.9 Ave. 45.4 32.3 Left Side 0 43.9 0 37.7 9 30.1 14.0 62.5 24.7 39.5 28.O 21.1 39.8 34.1 Right Side 11 8 19 9 14 0 12 1 47 8 13 5 37 7 26 0 15.2 20.8 21.9 28.1 39.0 25.7 25.9 19.2 13.9 14.5 . . .o 47.5 6O. 5 19.5 18.8 43.0 32.6 27.3 23.3 12.1 11.1 41.2 31.1 27.8 29.8 10.6 8.2 14.9 17.3 14.5 15.4 14.3 ...o 34.9 44.3 15.1 9.8 34.1 25.7 25.4 22.6 11.9 14.1 24.9 16.7 20.6 20.3 Not done. probably accounting for greater right side values. Table II shows the average percentage increase or decrease in scurf weights during each of the four treatment periods. These are computed from results obtained during the pre-treatment period. Figure 1 shows a comparison of the average weights from all subjects. Microbial Evaluation. Figures 2 and 3 represent bacterial plate counts and P. ovale slide counts respectively. During the pre-treat- merit period bacteria counts on both sides of the scalp averaged 50,000/ mg. During Period A when both sides were treated with tetracycline, counts were reduced to an average low of 200/mg. Values for both sides were similar and in no instance was a sample of scurf obtained which was entirely free of bacteria. During Period B when a suspension of bacteria was applied to the left side the counts varied considerably. The highest count recorded was