254 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS soap in all other basins for an aver- age of six subjects. The drop noted in basins 4, 5, and 6 was only slight from 2 per cent G-11 and only very little greater from the 4: per cent G-11 soap. The accuracy of the method is demon- strated in noticing slight effects and that the resident flora is reached in about the seventh basin, after which little change is noted. The result of this experiment was not striking. 3. Figure 3: A. In this experiment 70 per cent ethyl alcohol was used in Basin 5. Control soap was used in all other basins on an average of nine subjects. B. Seventy per cent ethyl alco- hol was used in Basin 5 for fifty seconds, only followed by washing with control soap for five seconds on an average of six subjects. C. Two per cent G-11 soap was used in Basin 5. Control soap was used in all other basins for an average •f nine subjects. In noticing the curve of this ex- periment it will be noted that when 70 per cent ethyl alcohol was used in Basin 5 (A), a decided drop oc- curred, but the count again rose in Basin 6 indicating that the alcohol probably did not kill as many bac- teria as was apparent from the drop, but rather had a coating effect which permitted the bacteria to be washed off in the next basin. The G-11 did not cause as large a drop, but neither was there the rise in the basin follow- ing its use. 4. In this series ofexperiments-- Fig. 4: A. Initial washings were done in all control basins for an average of six subjects. B. Control soap was used in all basins for an average of three sub- jects, who had used a control soap for a period of one week. Figure 4.--d, initial washings, control soap used in all basins. Average of 6 subjects. B, control soap used in all basins. Average of 3 subjects who had used control soap for the period of one week. C, control soap used in all basins. Average of 3 subjects who had used 2 per cent G-11 soap for a period of one week. Figures indicate that resident level was reached practically from second basin. C. Control soap was used in all basins on an average of three sub- jects, who had used 2 per cent G-11 soap for a period of one week. This experiment gave a striking result. It indicated that G-11 had not only wiped out the transient flora, but had greatly reduced the level of the resident flora and had brought the count down to an ex-

METHODS OF TESTING A GERMICIDE 255 tremely low level. Price, in his ex- periments on commercial soaps, had noted that' none of those tested by him had had any germicidal action on the resident flora of bacteria. 5. Figure 5: Because of the striking result of Experiment 4, it this subject an unexpectedly low count was encountered in the first basin 'and a reduction to the low level typical of all other subjects was found in all the other basins. 7. In this series of experiments the effect of 2 per cent mercuric ,.ooo.ooo •.ooo ooo 1_5oo•ooo •'• ,500.000 fl i • 5 7 9 0 •a ,i• Figure 5.--d, initial washings, con'trol soap used in all basins. Average of 14 sub- jects. B, control soap' used in all basins. Average of 4 subjects who had used control soap for a period of one week. C, control .soap used in all basins. Average of 10 sub- jects who had used 2 per cent G-11 soap for a period of one week. • ß . was repeated using a larger average group of subjects and the result• of the preceding experiments were con- firmed. 6. Figure 6: 'In this experimen• one of the subjects who had used G-11 soap for a week reported for his washing experiment directly from football practice with his hands very much soiled. E3-en in Figure 6.--d, initial w•.shings, control soap used in all basins. Average of 25 subjects. B, colony counts on one subject who had used 2 per cent G-11 soap for a period of one week. Control soap used in all basins. iodide contained in Neko soap was compared to the effect of 2 per cent G-1I soap (Figure 7): A. There was an initial washing with control soap in 'all basins for an average of six subjects. 'B. 'Control soap was used in all basins for an average of six sub- jedts, who had used 2 per cent Neko soap for a period of one week. C. Control soap was used in all basins on in aver'age of three •ub-