The medullated wool fiber
AuthorJ. F. Wilson
Author AffiliationsJ. F. Wilson was Assistant Professor of Animal Husbandry and Associate Animal Husbandman in the Experiment Station.
Hilgardia 4(5):135-152. DOI:10.3733/hilg.v04n05p135. June 1929.
Abstract does not appear. First page follows.
Classification of Hair Medullae
The classification of the various types of medullae found among all types of hairs has been described by Hausman.(1) Medulla types of infra-hominid hairs are shown as (a) absent; (b) discontinuous, in which the medullary substance is displayed at fairly regular intervals throughout the length of the shaft; (c) intermediate, in which the medullary cells are found so closely contiguous as to present a medulla unbroken but uneven in contour; (d) continuous, in which the cells of the central lumen are apparently completely anastomosed or so closely packed as to give a regular tubular appearance to the fiber; and (e) fragmental, in which the medulla is found only as an occasional fragment at irregular intervals. Medulla types of human head hairs are classified as (a) absent; (b) fractional, which is seemingly almost identical with the fragmental type among infra-hominid hairs; (c) broken, in which the medulla may be heavy but does not form a continuous canal; and (d) continuous. Hausman has shown that among the infra-hominid hairs the greatest hair-shaft diameters were found in those carrying the fragmental medullae, while in human head hair, the largest were associated with presence of the continuous medulla.
The writer’s examination of medullated wool fibers from several breeds of sheep, but largely from the Lincoln and Romney, indicates that the medulla types found in wool follow more closely Hausman’s classification for human head hair than that for infra-hominid hair, the coarsest fibers being associated with the continuous rather than with the fragmental medulla.
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