COMPARISON OF THE EFFECTIVENESS 789 (22) Sulzberger, M. B., Zak, F. G., and Herrman, F., jZ. invest. Dermatol. 12, 404 (1949) JL invest. DermatoL 9, 221 (1947). (23) Schneider, W., und Ruther, H., in: H. A. Gottron und W. Sch6nfeld (Herausgeber) Derma- tologie und k'enerologie, Band II/1, Georg Thieme Verlag, Stuttgart 1958, p. 379. (24) Horfi•ek, J., in: O. Braun-Falco und H.-J. Bandmann (Herausgeber) Fortschritte der prakti- schen Dermatologie und V'enerologie, 6. Band, Springer-Verlag Berlin-Heidelberg-New York 1970, p. 312. (25) Gordon, B. I., and Maibach, H. I., J. invest. DermatoL 50, 411 (1968). (26) Rovensk•, J., and Saxl, 0., J. invest. Dermatol. 43, 171 (1964). (27) Rovensk•, J., and Toman, M., •eskoslov. Dermatol. 36, 215 (1961). (28) Sarkany, I., and Caron, G. A., J. •dnatomy (London) 99, 359 (1956). (29) Zfihejsk•, J., Parfum., C'osmdt., Savons 13, 942 (1970). (30) Sulzberger, M. B., Griffin, T. B., and Wiley, H. S., Dermatologica (Basel) 135, 414 (1967). (31) Zfihejsk•, J., a Rovensk•, J., •eskoslov. Dermatol. 46, 7 (1971). (32) Horfi(ek, J., und Zfihejsk•, J., Dermatol. Mschr. 157, 145 (1971). (33) Adams, Th., J. appl. Physiol. 21, 1004 (1966). (34) Rovensk•, J., und Zahejsk•, J., XIII. Congressus Internationalis Dermatologiae, M/inchen 1967, Vol. II, Springer-Verlag Berlin - Heidelberg - New York 1968, p. 1020.

J. Soc. Cosmetic Chemisls 23, 791-802 (1972) Die Alkali16slichkeit als Kriterium fiir chemische und physikalische Verinderungen am Humanhaar G. A. ERLEMANN und H. BEYER* Synopsis--Alkali solubility - a criterion of changes in the physical and chemical properties of human hair. Bleaching, permanent waving, and oxidation colouring of human hair were studied in dependence on both time and hydrogen peroxide concentration. Alkali solubility and cysteic acid content of the respective samples treated in the ways mentioned above were de- termined and the results obtained represented graphically. It was found that, as expected, an increase in the cysteic acid content causes rising alkali solubility. This increase being linear, cysteic acid content may be assesses indirectly from alkali solubility. Since the cysteic acid content is of top importance with regard to the satisfactory condition of hutnan hair, alkali solubility presents itself as the most appropriate method to determine changes of human hair due to the effect of oxidants. Based on a cystine content of %9 [zmoles/g in untreated human hair, an alkali solubility of 1650 is indicative of about 220 [zmoles/g of cysteic acid fortned by oxidation processes corresponding to approxi- mately 1550 of the present cystine bonds oxidized and, therefore, no longer available for perma- nent waving. To make definite statements based on alkali solubility, a total amount of about 1.0 g of the hair sample is required to determine alkali solubility, whereas, for cysteic acid determination by low-voltage electrophoresis, 0.3 to 0.5 g, and by ion-exchange chromatography only 5 mg are sufficient. Die von Harris und Smith (1) eingeftihrte Alkali16slichkeit hat sich zur Auffindung von Ver•inderungen der Wolle nach der Behandlung mir S•iuren sowie Oxidations- oder Reduktionsmitteln vielfach bew•ihrt (2). Das Prinzip dieset Methode beruht darauf, dab Wollproben unter Standardbedingungen mir 0,1 N Natronlauge behandelt wetden, und der Gewichtsverlust danach als Differenz zwischen dem Trockengewicht der Probe vor und nach der Behandlung bestimmt wird (3). Bei der oxidativen Behandlung von Faserproteinen wetden Cystinbin- dungen in Cysteins•iurereste iiberfiihrt, bei einer reduktiven Behandlung entstehen dagegen Cysteinylreste. Derart behandelte Faserproteine besitzen * Panteen Forschungs- und Entwicklungslaboratorien, CH-4002 Basel (Schweiz).--Adresse: Dr. H. Beyer, c/o F. Hoffmann-La Roche & Co. AG, Grenzacher Str. 124, CH-4000 Basel 791