QUANTITATIVE ASPECTS OF CORNEOCYTES 3 2 Figure 2. Turbine apparatus. Detail of the chamber. 1--propeller 2--chamber. STANDARD CONDITIONS A preliminary study was made to define the standard conditions: propeller material (in relation to the quality of cells), rotating time, and motor speed (in relation to the number of cells). Figure 3 shows that numeration increases linearly with motor speed. 10 Z5 2.5 , Corneocytes/cm R.P.M. x 10 • 0 5 10 15 2'0 25 •0 Figure 3. Number of corneocytes extracted per cm • of skin surface in relation to motor speed (R.P.M.) for a fixed period of 1 minute. Arrow indicates the 2500 R.P.M. used in standard conditions.

4 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 30 ÷ 2O 10 Corneocytes/cm • X 10 3 Second ' 120 Figure 4. Number of corneocytes extracted per cm 2 of skin surface in relation to rotating time of the turbine. Arrow indicates the one minute used in standard conditions. --O-- motor speed 2500 R.P.M. subject male, 35 years old. --O-- motor speed 350 R.P.M. subject female, 25 years old. Table I Individual Results: Cell Count, Quality, and Projected Area of Corneocytes Cell Count Number/cm2/min Broken Normal Mean Area + S.E. Subject "Turbine" Cells % Cells % Aggregates % for Normal Cells/•m 2 1 24 000 N.D. N.D. N.D. 1 005 _+ 8 2 7 800 15 73 12 990 _+ 12 3 2 820 5 62 33 700 + 18 4 10640 6 77 17 815 + 11 5 6 800 10 68 22 930 + 11 6 6240 8 82 10 814_+ 5 7 1 570 15 60 24 673 + 21 8 2 990 6 75 20 760 + 19 9 3 440 11 58 32 720 _+ 12 10 5 920 11 81 8 946 + 7 11 34 500 7 44 49 1 030 + 7 12 20 100 12 69 19 1 000 + 8 13 12 500 15 70 15 912 + 8 14 31600 7 70 23 807 + 10 15 8 200 8 72 20 900 _+ 12 16 2 880 11 76 13 795 + 13 17 2 600 10 68 22 788 _+ 9 18 2 650 24 70 6 828 + 15 19 11 700 8 79 13 958 m 8 20 16 100 5 78 17 825 + 15 Mean 10 750 10 70 20 860 + S.E. 2 190 1 2 2 24