48 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS studied and a more scientific basis realized for manufacturing control. This could be particularly useful in determining the permissible latitude in operating conditions to meet finished product standards. CONCLUSIONS The explanation for the generally wide use of the 55 per cent palmitic- 45 per cent stearic acid proportions occurring normally in commercial stearic acid may have its basis in the phenomena just discussed. Consider the combination of properties provided: 1. Melting point is at a relatively flat part of the curve. 2. Relatively larger crystals are obtained than with mixtures containing smaller or larger palmitic/stearic acid proportions. 3. Specific volume is at a minimum. 4. Molar proportions are approximately equal. 5. Solubility is near the maximum value obtained at the eutectic. 6. X-ray diffraction pattern indicates presence of a single form--the stable C type of the pure components. There are many problems in the development of cosmetic formulations. Questions on the physical characteristics, performance properties, and con- sumer acceptance of a particular product are complicated by factors out- side those mentioned in this review, such as odor, color, pearlescence, shrinkage, hardness, toughness, and texture. In many cases, practical experience in formulations and manufacturing conditions has been the major basis for the development of satisfactory products. Basic physical chemical data of such complex mixtures are not available as they must be developed for each formulation. However, more basic data on the physical chemical characteristics of cosmetic formulations should be considered a practical matter in their development. Such knowledge is useful in arriving at a scientific basis for satisfactory formulations and in determining the latitude in formulation and manufacturing conditions to obtain the desired uniformity of quality in the final products. BIBLIOGRAPHY (1) Bailey, A. E., "Melting and Solidification of Fats," New York, Interscience Publishers, Inc. (1950). (2) Ralston, A. W., "Fatty Acids and Their Derivatives," New York, John Wiley & Sons, Inc. (1948). zfcknow/edgment: The author is indebted to Dr. E. S. Lutton and Dr. F. B. Roseyear for their advice and helpfulness in providing some of the physical-chemical data for this paper.

Location of Books on COSMETIC FORMULATIONS Accessible to the Cosmetic Chemist in the New York Metropolitan Area By Library Committee, Society of Cosmetic Chemists, S. J. STR•^NSE, Chairman and P. G. L^vvFER CODEl BM--Bristol-Myers Products Division BPL--Brooklyn Public Library CC--Chemists' Club CP--Colgate-Palmolive Company CU--Columbia University DA--Department of Agriculture DH--Department of Health, Educa- tion and Welfare (National Institute of Health, Bethesda) ER--Evans Research and Develop- ment Corporation FB--Fritzsche Brothers GD--Givaudan-Delawanna, Inc. LC--I.ibrary of Congress LF--Lehn & Fink Products Corpora- tion NYPL--New York Public Library NYU--New York University (Washing- ton Square Library) WH--Warner-Hudnut Company, Inc. AUTHOR AND NAME OF PUBLICATION Adair, Grace M.: Adair's cosmetology examiner. 1937. NYU American Medical Association, Bureau of Investigation: DH Cosmetics and allied preparations. Chicago, 1936. American Medical Association: Cosmetics and applied NYU preparations. 1937. Askinson, George William: Parfumerie-fabrikation. CC Leipzig, 1905. Askinson, George William: Perfumes and cosmetics their preparation and manufacture. New York, 1915 5th ed., 1922 and 1924. Askinson, George William: Perfumes and their prepa- ration. New York, 1907. Bames, Herbert O.: Essentials of cosmetology. 1936. Beerbohm, Max: A defense of cosmetics. New York, 1922. Begy, Joseph: Practical handbook of toilet preparations and their uses. New York, c. 1889. Belanger, Emil: Drug and specialty formulas. 1941. Bennett, Harry: The cosmetic formulary. New York, 1937. LOCATION BPL (1922) CC (1924) CP (1922) CU (1915 & 1922) DA (1922) ER (1922) LC (1915) LF (1915) NYPL (1915) WH (1915) CC NYU LC LF NYPL LC NYPL BM BPL DA LC NYPL NYU BM BPL CU DA DH ER FB LC LF NYPL NYU