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SummaryA study is made of the disruption of wool by ultrasonic disintegration and the separation and identification by microscopy of the major components of the fibre. The ultrasonic disintegration process is investigated empirically in order to establish the conditions under which maximum rates of disruption occur. Of a large number of liquids examined it is found, in confirmation of earlier work, that the rate of disintegration of wool is very slow in water but usually increases in amount as the swelling of the fibre increases. The several exceptions to this rule show that there are other factors of secondary importance in determining the rate of disruption. The amount of disruption is sufficient for preparative purposes and increases in amount in the series dimethyl sulphoxide, formic acid, and dichloroacetic acid.Cortical cells, cuticle, and disrupted cortical cells can be separated on the basis of their different sizes by a combination of screening and sedimentation methods. The histological purity of the fractions is established by light and electron microscopy. It is also shown that the random nature of the ultrasonic disruption process results in the production of components of a continuous range of sizes from cortical cells down to needle· like components of size approaching that of microfibrils.

SummaryAmino acid analyses have been made of five different samples of cortical cells, 10 samples of cuticle, and 17 samples of whole fibres from various placental mammals, marsupials, and monotremes. There were no consistent differences in analyses between these three subclasses of mammals. Although there are considerable differences in amino acid analyses among the fibres from the various animals, nevertheless these differences are less than those between the analyses of whole fibres and cuticle. Thus the amino acid analyses of all keratin fibres have been averaged to give a result which is characteristic for keratin fibres. Similarly an average value is given for the amino acid analyses of cortical cells (which is very close to that of whole fibres), cuticle, and medulla.The large amount of citrulline in medulla and small amount in cortical cells and cuticle allows this amino acid to be used as a marker, from which the medulla content of fibres can be calculated. It is found that platypus fibres contain 16% medulla, and rabbit fur and red kangaroo fibres about 13 and 9 % medulla respectively.

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