Examination of the fine structure of wool by X-ray analysis

During recent years an exhaustive study has been made of the elastic properties of wool fibres under widely different conditions of temperature and relative humidity. It has been shown (1) that the elastic properties of the fibre as a whole are those of the single cell, which consists essentially of an elastic cell-wall enclosing a fibrillar structure, which is not haphazard but is usually disposed along the axis of the fibre. The enveloping cell-wall remains perfectly elastic up to 70 per cent. extension in water at ordinary temperature but the fibrillar structure under similar conditions is plastic. Extended fibres may undergo permanent alteration either by rupture or by plastic flow of fibrillæ, but invariably retain their ability always to return to their original length in water at ordinary temperatures, on account of the perfect elasticity of the enclosing cell-wall. The plasticity of the fibrillar structure, which is so marked in water at ordinary temperatures, is scarcely measurable in atmosphere below 75 per cent. relative humidity. Such information regarding the structure of wool fibres has been derived almost entirely from a study of their stress-strain relationships, and it was considered that the validity of the general theory should be examined by a totally different method. An examination of the fine structure of wool fibres by X-ray analysis should disclose structure within the cell and its variation under changing conditions of stress and humidity.