Improved fibre preparation technique for methylene blue staining of wool fibres

Ortho- and paracortex can be differentiated in wool fibres by a methylene blue staining procedure. The procedure, though effective, is slow and tedious because of the method currently used for fibre preparation. The aim of this study was to simplify the fibre preparation technique. Wool fibre bundles, obtained from midside wool samples, were cleaned in solvent and dried. Cotton thread was tied to the tip of each fibre bundle which was then drawn through a length of fine Silastic tubing. The bundles were hardened by firstly soaking in nitrocellulose then chloroform. The tubing was removed from around the bundles, and the fibre bundles were dried, trimmed, and cut into lengths (10 mm) which were then immersed in molten paraffin, embedded in paraffin blocks, and sectioned. The fibre sections were stained using a methylene blue staining protocol. This technique has proved to be an efficient and effective means of identifying regions of ortho- and paracortex within wool fibres.