FIXED PHASE OR CARRIER IN CHROMATOGRAPHY 101 with cross-sectional area of hair. It was shown that "problem" hair has a higher Trotter Index (nearer a circular shape) than normal hair of the same degree of medullation, and a lower incidence of medullation than normal hair of the same Trotter Index. dcknowledgements: The authors wish to express their appreciation for the skilled assistance of W. F. Munn and Mrs. Elsa Knitl in taking the photomicrographs. REFERENCES (1) Shillaber, C. P., "Photomicrography in Theory and Practice," John Wiley and Sons, Inc., New York (1945). (2) Barnard, J. E., and Welch, F. V., "Practical Photomicrography," Arnold Publishers, London (1936). (3) Wildman, A. B., "The Microscopy of Animal Textile Fibres," Wool Industries Research Association, Torridon (1954). (4) Heyn, A. N.J., "Fiber Microscopy," Interscience Publishers, Inc., New York (1954). (5) Munn, W. I5'., U.S. Patent No. 2,537,846, January 9, 1951. (6) Munn, W. I5'., Research Comments, 3, No. 1 (1951). (7) Munn, W. I5'., and Evans, R. L., Proc. Sci. Sect. Toilet Goods aissoc., May (1952). (8) Munn, W. I5'., Exakta, 2, 2, 6 (1953). (9) Trotter, M., and Duggins, 0. H., aim. 5•. Phys. ainthropoL, 6, 489 (1948). (10) Mercer, E. H., Textile Research pc., 23, 388 (1953). (! 1) Horio, M., and Kondo, T., Ibid., 23, 373 (1953). (12) Dusenbury, J. H., and Jeffries,•,., •7. Soci Cosmetic Chem., 6, 355 (1955). (13) Duggins, O. H., and Trotter, M, aim. 5•. Phys. ainthropoL, 8, 399 (1950). SOME REMARKS ON THE NATURE OF THE FIXED PHASE OR O F THE CARRIER IN GAS-LI QUID PARTI- TION CHROMATOGRAPHY OF ESSENTIAL OILS AND AROMATICS* By YvEs-RENf• N^vEs, D.Sc. L. Givaudan and Co., Ltd., Vernier, Geneva, Switzerland WE s•ovI.•) on no account neglect or underrate the fact that the constituents of essential oils or aromatics may be altered on contact with the fixed phase or the carrier in gas-liquid partition chromatography. Most of the constituents of the essential oils and most of the aromatics have to be examined by gas-liquid partition chromatography at relatively high temperatures because of the prerequisites for the functioning of the usual detectors. Substances used for the fixed phase or as carriers which are appropriate for the analysis of less fragile substances or at lower temperatures are quite unsuitable here. It is considered necessary to mention these facts because some workers appear to be unaware of them, and others underrate their importance. It is essential that an analytical technique, whose use can be invaluable * Presented at the August 2, 1957, Meeting, Geneva, Switzerland.

FIXED PHASE OR CARRIER IN CHROMATOGRAPHY 101 with cross-sectional area of hair. It was shown that "problem" hair has a higher Trotter Index (nearer a circular shape) than normal hair of the same degree of medullation, and a lower incidence of medullation than normal hair of the same Trotter Index. dcknowledgements: The authors wish to express their appreciation for the skilled assistance of W. F. Munn and Mrs. Elsa Knitl in taking the photomicrographs. REFERENCES (1) Shillaber, C. P., "Photomicrography in Theory and Practice," John Wiley and Sons, Inc., New York (1945). (2) Barnard, J. E., and Welch, F. V., "Practical Photomicrography," Arnold Publishers, London (1936). (3) Wildman, A. B., "The Microscopy of Animal Textile Fibres," Wool Industries Research Association, Torridon (1954). (4) Heyn, A. N.J., "Fiber Microscopy," Interscience Publishers, Inc., New York (1954). (5) Munn, W. I5'., U.S. Patent No. 2,537,846, January 9, 1951. (6) Munn, W. I5'., Research Comments, 3, No. 1 (1951). (7) Munn, W. I5'., and Evans, R. L., Proc. Sci. Sect. Toilet Goods aissoc., May (1952). (8) Munn, W. I5'., Exakta, 2, 2, 6 (1953). (9) Trotter, M., and Duggins, 0. H., aim. 5•. Phys. ainthropoL, 6, 489 (1948). (10) Mercer, E. H., Textile Research pc., 23, 388 (1953). (! 1) Horio, M., and Kondo, T., Ibid., 23, 373 (1953). (12) Dusenbury, J. H., and Jeffries,•,., •7. Soci Cosmetic Chem., 6, 355 (1955). (13) Duggins, O. H., and Trotter, M, aim. 5•. Phys. ainthropoL, 8, 399 (1950). SOME REMARKS ON THE NATURE OF THE FIXED PHASE OR O F THE CARRIER IN GAS-LI QUID PARTI- TION CHROMATOGRAPHY OF ESSENTIAL OILS AND AROMATICS* By YvEs-RENf• N^vEs, D.Sc. L. Givaudan and Co., Ltd., Vernier, Geneva, Switzerland WE s•ovI.•) on no account neglect or underrate the fact that the constituents of essential oils or aromatics may be altered on contact with the fixed phase or the carrier in gas-liquid partition chromatography. Most of the constituents of the essential oils and most of the aromatics have to be examined by gas-liquid partition chromatography at relatively high temperatures because of the prerequisites for the functioning of the usual detectors. Substances used for the fixed phase or as carriers which are appropriate for the analysis of less fragile substances or at lower temperatures are quite unsuitable here. It is considered necessary to mention these facts because some workers appear to be unaware of them, and others underrate their importance. It is essential that an analytical technique, whose use can be invaluable * Presented at the August 2, 1957, Meeting, Geneva, Switzerland.