Within the past year I heard in a university class in organic chemistry the statement that the cleansing action of soap depended upon the alkali formed by hydrolysis of the soap. This statement was made without qualification; Since then I have noticed in a few books treating the subject, what seemed to me over-emphasis of the role played by the alkali in the cleansing. To my notion ,the treatment in Alexander Smith's Elementary Chemistry is one of the most satisfactory explanations I have seen.

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... Besides the arguments given by Professor Smith against the ability of the alkalies formed from the hydrolysis of soap to act as cleansing agents, I would suggest a simple experiment which can easily be tried in the home. Place some greasy dishes in a pan of water. Add household ammonia until the water is ammoniacal (washing soda might also be used, being added until water is distinctly alkaline, this being tested by the "soapy" feeling), then try to wash the dishes. After washing a few, hold a bar-of soap under the water and shake it back and forth until permanent suds are formed. Now wash a few" more dishes. The greater ease with which the grease is removed will readily become apparent. This large increase in the efficiency of the "dish-water" is certainly not due to any great increase in the alkalinity. However, the alkalinity of soap solutions, disregarding the effect upon the power of cleansing, is not without importance. If five brands of soap be procured, a concentrated solution of each of these in distilled water at room temperature be made, and this solution titrated against decinormal acid, methyl red or methyl orange being used as indicator, the results will make very interesting discussion in a class of students who have become familiar with the action of alkalies upon the skin, the hair, and various fabrics. In carrying out the experiments the students were required to .mjake a sufficient number of titrations to get results'that checked fairly well. ..In each trial 30-35. c. c. of the §oap solution were run out of the burette. The reason: for taking.this volume instead of 5-10 c. c. was discussed, with considerable profit. It has been my experience that students left to themselves are apt to use small volumes in titration (perhaps to save refilling their burettes) overlooking the fact that the per cent of error is increased considerably by so doing.