JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Such data must, of course, be interpreted with care for the hair-reagent system is a complex one and the meaning of "activation energy" is open to question. If, however, such values are calculated by classical methods the results may give some indication of the type of reaction involved. For example, the energy of activation of the reaction between cuprammonium hydroxide and wool is about 18 k cal. This is lower than that expected for a true chemical reaction, and supports the view that the copper is co- ordinated with the groups in the main peptide chains, and that the reaction between keratin and cuprammonium hydroxide is primarily one of exchange between the ligands initially attached to the copper and groups in the fibre. DR. A. W. HOL•tES : I found the work which you carried out on the esterification of hair, and subsequent setting, most interesting, but I find it difficult to believe that esterification occurs in five minutes at 50øC, or in 1 hour at 10øC. I feel that we must look for some other explanation of the improved setting properties. THE LECTURER: I agree. My main reason for giving the data was to stress that the reaction is dependent on temperature. At high temperatures the predominating reaction is almost certainly one of esterification but the changes taking place at lower temperatures require further investigation. I have consequently stressed that the mechanism, by which the above treatments facilitate setting, is not yet completely understood. MRS. H. BUTLER: You indicated in your introduction that keratin treated with silicone retains oil more tenaciously than untreated hair. Do you have any results for the effect of comparable carbon compounds ? THE LECTURER: No. Exactly analogous carbon compounds are not readily available, but I would expect carbon-type water repellents to behave in a similar manner. MR. E. A. GOODE: Could you explain a little more about the role of hydrogen bond breakers in setting ? Which substances other than urea can be used for this purpose ? THE LECTURER: The role of hydrogen bond breakers is a complex one. They do not promote setting when used alone, but they do increase the effectiveness of disulphide bond breakers such as bisulphites. The use of mixtures of bisulphites and hydrogen bond breakers is covered by patents. It would appear that the disulphide bond breakers act rather like a key, opening up the fibre so that the hydrogen bond breakers can be effective. Other hydrogen bond breakers include lithium bromide, thiocyanates, and metallic ammines. Many of the latter are coloured, but zinc ammines and reduced copper ammines are not.

J. Sec. Cosmetic Chemists 15 437-446 (1964) ¸ 1964 Society of Cosmetic Chemists of Great Britain iDIFFUSE ALOPECIA IN WOMEN: ITS CLINICAL FORMS AND PROBABLE CAUSES E. LUDWIG, Dr. Med.* Presented at the Symposium on "Hair", at Brighton, Sussex, on 16th April 1964. Three •lifferent lorms el •liffuse •emale alopecia are •lescribe•h Arguments 'are presentetl which •avour the concept o• the itlentity be[ween common -baldness (male pa•ern alopecia), and tlif•se alopecia in women. Both con. ditions are shown to be the result o• antlrogenic stimulation o• genetically l•retlisposed hair •ollicles. The available results o• determinations o• urinary •excretion o• antlrogens are reportetl. For many centuries Aristotle's statement that women, children, and •eunuchs never become bald has been of unchallenged validity. Sabouraud (1) seems to have been the first to report the occurrence of diffuse alopecia in women, which he considered a true seborrheic baldness (calvitie vraie, s6borrh6ique chez la femme). Since then many authors (2,3,4,5,6) have .confirmed Sabouraud's observation and agree that diffuse alopecia is of more frequent occurrence than is generally believed. Several European authors (7,8,9,10,11), and Sulzberger et al (12) in the U.S.A. have even •expressed the view that an actual increase in the incidence of female balding has taken place in recent years. SUBJECTS Among the female patients attending the special clinic for diseases of the scalp and hair at our hospital, from 1961 to 1963, there were 102 patients with obvious diffuse thinning of the hair. However, this number was far exceeded by patients complaining of hair fall, where no reduction in the amount of hair was perceptible. DIFFERENCE BETWEEN ALOPECIA AND EFFLUVIUM It seems advisable to emphasize that we are employing the term alopecia only to designate an actual reduction in the amount of hair, i.e. different degrees of hairlessness ranging from a just perceptible thinning to an un- equivocal lack of hair. Whenever referring to the process of losing hair *Dermatological Clinic, University of Hamburg, Germany. 437