12—Morphology of the Cuticle Layer in Wool Fibres and Other Animal Hairs

Abstract

The paucity of information about the fine structure of cuticle cells, in animal hair and wool fibres, has been a major factor in the general failure to advance a theory capable of explaining quantitatively the origin of the Directional Frictional Effect. Electron microscope studies have been made covering : (i) surface replications, (ii) examination of fibre profiles, and (iii) thin sectioning. Significant differences have been found between the surface textures of replicas of various wool fibres. However, because of the lack of equipment for the quantitative interpretation of stereo electron-micrographs, the direct examination of fibre profiles was undertaken. Thus, information was obtained about the height and frequency of the distribution of cuticle cell edges along the fibre axis, together with other information about the surface asperities. Thin sections (both transverse and longitudinal) yielded information about the type and extent of radial and peripheral overlapping of cuticle cells ; also, the various ways in which they are attached to their neighbours. The idealized model of a cuticle cell, emerging from these studies, could account for the two distinctly different mechanisms of deformation, namely buckling and compression, under forces acting in the direction of fibre-root and fibre-tip respectively. Evidence was obtained providing further, if not conclusive, proof of the “ploughing” action, operative during motion in the tip-to-root direction.