Anomalies in the Microscopic Structure of Some Wools

Abstract

THE bilateral division of the cortex of merino wool into ortho and para sections has been clearly shown by many workers^1,2, and can easily be demonstrated by dyeing the fibres with methylene blue at the boil, at pH 7.4. When this experiment is carried out with Southdown or Corriedale fibres the shape of the two portions is often anomalous. Near the division between stained (ortho) and unstained (para) portions there often appears a core, often within the para-cortex, but stained more deeply than the ortho. When the experiment is repeated at pH 6 (at which very little segmentation is discernible in Merino) this core remains deeply stained and clearly distinguishable from the ortho-cortex, which is relatively pale (Fig. 1). It is concluded from this experiment, and other similar experiments with fine crossbred wools, that in some types of wool a core more basophilic than the ortho-cortex exists, usually at the junction between the ortho and the para portions, and sometimes completely in the para-cortex. In a sample of Southdown fibres one-third had such a core, and in Corriedale about two-thirds. When whole fibres are examined this core is towards the inside of the curve of the crimped fibre. It is proposed to call this core the meta-cortex.