The use of the pressure technique has shown that measurements of the elastic and plastic response of individual fibres can be correlated with the inherent structure of the fibres, with the type of tanning used, and with the action of solvents, etc. Qualitative work has indicated that the separation of fibres under pressure is closely dependent upon their state of hydration and that the rate of loss of moisture may govern fibre identity upon drying. Excessive drying temperatures or rates are associated with changes in the array of fibres in the dried bundle, and the surface appearance of the fibres can be emphasised by the interferometric technique. Morphological variations have been associated with marked differences in behaviour under pressure, and with markedly different end products, i.e. fragments or fibrils which assume characteristic shapes.