37—the Histological Structure of Wool Fibres and Their Plasticity

The relation between the creep behaviour (plasticity) and the proportion of the orthocortical material (expressed as ortho/para ratio) in five lambs' wools has been examined by means of electron-microscope techniques, in conjunction with thin sectioning. No correlation was found between the amount of orthocortical material, on the one hand, and either plasticity or helical conformation (the latter estimated by other workers) on the other. These results are supported by the observation of the structural differences, greater than hitherto thought, within both cortical segments (as indicated by the considerable variation in metal absorption—‘staining’), and it is believed that these have the primary effect on the plasticity. The cells of intermediate morphological appearance and reactivity (between those of the two bilateral segments and referred to as as meso-type) have a secondary influence in this respect.