Morphological comparison of the cross section of the human and animal hair shafts by scanning electron microscopy.
In order to obtain some fine structural informations available for the identification of hair samples collected in small amounts or fragments, the preparation method of the samples for the scanning electron microscopy was investigated. Hair samples of human individuals and animals were mounted between two sheets of celluloid using isoamyl acetate and were sectioned to 20 microns thickness. These sections were collected in a test tube for dissolving the celluloid. After centrifuging in acetone, a small mass of sections was embedded in Spurr's epoxy resin. After polymerization, 1 micron thick sections were made on an ultramicrotome. The sections were mounted on glass slide and were surface-etched by exposure to oxygen plasma for 90 seconds. Observations were made in the secondary electron image mode of a scanning electron microscope. After surface-etching, a good resolution of the cross section was obtained. The arrangement of the cortical cells of human hairs was observed to be fairly irregular with conspicuous interdigitations of cell boundaries as compared with that of animal hairs. The medulla of human and animal hairs were filled with cellular remnants of destroyed medullary cells showing fibrous structures. The lamellar structures of cuticular cells became very clearly visible. The number and the overall thickness of cuticular cell layers in human and animal hairs investigated varied considerably between scalp and pubic hairs and from animal to animal.
D000328:Adult; D000818:Animals; D001188:Artiodactyla; D002335:Carnivora; D006197:Hair / Q000648:ultrastructure*; D000882:Haplorhini; D006736:Horses; D006801:Humans; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008875:Middle Aged; D051381:Rats; D012589:Sciuridae; D013045:Species Specificity