pH EFFECTS ON SKIN 151 7.0 6.5 6.0 5.0 4.5 .. 0 • • • l! • , , , 1 2 3 10 17 2• :•1 3•8 •5 52 5•9 t (d) Figure l. Development of the pH values on the forehead from washing with synthetic detergent prepa- rations at pH 5.5 and 8.5. 7.0 6.5 6.0 4.5 , , !! , , , , , t (d) Figure 2. Development of the pH values on the forearm from washing with synthetic detergent prepara- tions at pH 5.5 and 8.5.

152 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 9.0- 8.5- 8.0- 7.5- 7.0- o•6.0 - -- 5.5- 5.0- 4.5- 4.0 3.5 3.0 1 2 3 110 17 24 31 38 45 52 59 t [dl Figure 3. Development of the counts of coagulase-negative staphylococci per square centimeter on the forehead from washing with synthetic detergent preparations at pH 5.5 and 8.5. 6.0- 5.5- 5.0- 4.5- t4.0- 3.5- 3.0- 2.5- 2.0- 1.5- 0.5- 0 T T , , , // ] , , , , , , , 1 2 3 10 17 24 31 38 45 52 59 t (dJ Figure 4. Development of the counts of coagulase-negative staphylococci per square centimeter on the forearm from washing with synthetic detergent preparations at pH 5.5 and 8.5.