4 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS •d o 0 c,') ß

ANTIPERSPIRANTS 5 recorded, they were applied to cot- ton strips in the usual manner, and incubated for 24 hours at 85% R.H. and 80øF. A section of the treated area was then cut out and the pH determined directly on it. If the cream had "bled," as occurred in two cases, the pH of that portion of the strip was also taken. Other sections of each strip were pressed-- with the ironer set at 275-295øF. -- for periods of 5, 8, 10, 12 and 15 seconds. Other sections were ex- posed in the oven at 100øC. for 15 minutes, 30 minutes, 1 hour, '11/2 hours and 2 hours. pH values were recorded on all of them. One set, after pressing for the standard 10 seconds, was reconditioned for three hours at 85% R.H. and 80øF. before the pH readings were taken. The results are summarized in Table 3. The source of heat--ironer or oven--appears to have a definite bearing on the picture of pH change. This may explain to some extent our difficulties in correlating the two methods. These results may also be helpful, in the formulation of new products, through study of the pattern and level of pH change in formulas giving minimum fabric destruction. I was particularly in- terested in the figures for samples Nos. 1 and 2. These were the same two creams used in the second series of oven tests (Table 2). The pH of cream No. 1, which showed little in- crease in destruction after the first hour, rose steadily in the oven dur- ing the second hour. On the other hand, there was a significant drop in the pH of cream No. 2 between 11/2 and 2 hours--the period during which the destruction jumped 10%. Also interesting is the drop in pH which occurred in seven out of the eight cases between 8 and 10 sec- onds' ironing, and the sharp rise which occurred when the strips were reconditioned for three hours. This points up the importance of accurate timing in these investigations. Since all this emphasizes the pres- ent necessity for sticking to the ironing procedure, while .re-empha- sizing the need for further standard- ization of the method, perhaps the next step is to bring out even more clearly the points in the procedure where inaccuracies may occur, lead- ing to lack of agreement in the re- suits of different workers. The idea occurs to me that lowering of the ironing temperature with propor- tional extension of the pressing time might be something to look into. We have long wanted to collect more complete data on the effects of perspiration itself on fabric. This has not been easy since we have trained our testing groups to habits of good grooming so well that they are now completely unwilling to go without deodorant protection. We have managed to get, at long last, a set of figures. The usual procedure for practical use investigation was used, with two modifications. Nothing except distilled water was used on the armpits, and an attempt was made to record pH values in the axillar area. This latter was done at the end of each day, by swabbing the underarms with a piece of filter paper, and determining pH on a