34 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS quiescent follicles is quite different. Since the bulb of the active follicles degenerates, the plexus of capillaries around it collapses in a bundle at the base of the dermal papilla. The papilla itself flows away from the tufts of capillaries and comes to rest iminediately above it. Just below the entrance of the sebaceous gland, hair follicles are sur- rounded by a collar of sensory nerves that record pressure stimuli. Oddly enough, these nerves are rich in cholinesterase, like the nerves of t•he para- sympathetic nervous system. These sensory nerves are particularly in evidence around the nerves of the scalp. "THE HISTOCHENIISTRY OF THE HAIR FOLLICLE" OTTO BRAuN-FA•.CO Joh. Gutenberg-Universitlit Hautklinik, Main,, Germany. This paper presents a review of the histochemical findings in human hair follicles. Of the inorganic substances, calcium, magnesium, zinc, copper, sulphates, phosphates and iron have been investigated in quiescent and active hair follicles. The distribution of glycogen, PAS-positive but diastase resistant material and acid mucopolysaccharides in and around hair follicles is different during the different stages of hair growth. These substances are much more abundant in growing than in resting hair follicles. For the first time the histotopography of lipids, and especially that of phospholipids, unsaturated lipids and plasmal, has been reported fully in the different parts of the hair follicle. Amino acids, protein-bound sulphydryl groups and disulphide groups, as well as nucleic acids, have been studied during different stages of hair growth. The histochemical localisation of enzymes in the hair follicles is particularly important. Phosphorylase, succinic dehydrogenase, cytochrome oxiduse, esteruses, acid and alkaline phos- phatases, 5-nucleotidase, glucose-6-phosphatase, cholinesterase,/•-glucuroni- duse, amino-peptidase and carbonic-anhydrase have been studied and an attempt has been made to deduce their functional importance in relation to hair growth. Histochemical studies of hair keratinisation are somewhat hampered by technical limitations of the methods used for the identification of keratin. The histocnemical composition of trichlohyalin and of the keratinisation, the sigrificance of the nuclei in relation to keratinisation, and the fate of the nuclei during keratinisation are discussed. "THE ELECTRON MICROSCOPY OF THE HAIR FOLLICLE" E. H. M•Rc• Chester Beatty Research Institute, Royal Marsden Hospital, London, S.W. 3, England. Thin sections of a variety of kerati•ised tissues, hair, skin, feathers, etc., show that a continuous structureless dermal-epidermal membrane (ca.

ABSTRACTS OF PAPERS ON THE BIOLOGY OF HAIR GROV•TH 35 400 A. thick) separates the epidermis from the dermis. The basal layer of epidermal cells, usually somewhat columnar, are attached to the dermal- epidermal membrane, but their plasma membranes are separated from it by a less dense layer. The epidermal {Malpighian) cells contain small mitochondria, agranular vesicles (Golgi type), and large numbers of dense ribonucleoprotein (RNP) particles which are not associated with the membranes to form an endo- plasmic reticulum such as occurs in protein secreting cells. Fibrous keratin first appears as wispy bundles of fine filaments (100 A.) which in hair and feather rapidly aggregate to form definite fibrils lying parallel to the lengthening cells. In skin the filaments show a lesser tendency to form bundles and the orientation is more random. Frequently, the fibrils seem to sprout from the plate-like cell contacts {see later). In the hair cortex the bundles of filaments grow in length and width and, above the bulb constriction, stain more readily with the osmium fixative. High resolution micrographs show that the stain is associated with a material between the original filaments. It is proposed, therefore, that fibrous keratin is a duplex structure consisting of a system of fine parallel •-filaments (ca. 60 A. diameter) cemented together with a material high in cystinc and probably not fibrous (T-component). In the inner root sheath trichohyaline granules accumulate at first and later transform into fibrils. A similar change probably takes place in the keratohyaline of skin. Epidermal tissues show several remarkable, specialised cell contacts. In skir, outer root sheath and feather, these take the form of localised plates comprising a thickened cell membrane and several layers of dense material within the cytoplasm "backing." Fibrils may sprout in tufts from the plates. At higher levels several layers of intercellular material appear between the "plates." A similar dilation of the membranes, with the interpolation of intercellular sheets, occurs generally in the hair and is most marked in the cuticle and inner sheath. These contacts may be associated with strengthen- ing the formations. "THE CHEMISTRY OF KERATINISATION" A. GEDEON M.•TOLTS¾ In the early stage of keratinisation, the formation of cytoplasmic fibrils appears to be a basic mechanism which later becomes associated with decom- position and elimination of certain cytoplasmic and nuclear elements. Although these are common properties of keratinising cells of both hair cortex and epidermis, the actual mechanism of keratinisation is different. In the differentiating cells of the hair cortex, the cytoplasmic fibrils gradually reach a high concentration and the cells practically consist of fibrils when the nuclear and cytoplasmic activities cease. A quite perfect elimination of