. Electron microscopy; proceedings of the Stockholm Conference, September, 1956. Electron microscopy. Fig. 1. Cortical ceil isolated from Australian merino wool and exposed to ultrasonic vibrations, in uater. for 12 hours. Magnification 10,000. Fig. 2. Cortical cell isolated from Lincoln wool and exposed to ultrasonic vibrations, in water, lor 12 hours. Magnification 29,000. Fig. 3. Cortical cell isolated from Lincoln wool and exposed to ultrasonic vibrations, in lithium bromide solution, for 4 hours. Magnification 21,000. Fig. 4. Fragment of cortical cell isolated from Lincoln wool and expose
. Electron microscopy; proceedings of the Stockholm Conference, September, 1956. Electron microscopy. Fig. 1. Cortical ceil isolated from Australian merino wool and exposed to ultrasonic vibrations, in uater. for 12 hours. Magnification 10,000. Fig. 2. Cortical cell isolated from Lincoln wool and exposed to ultrasonic vibrations, in water, lor 12 hours. Magnification 29,000. Fig. 3. Cortical cell isolated from Lincoln wool and exposed to ultrasonic vibrations, in lithium bromide solution, for 4 hours. Magnification 21,000. Fig. 4. Fragment of cortical cell isolated from Lincoln wool and exposed to ultrasonic \ibrations, in lithium bromide solution, for 4 hours. Magnification 32,000. differences in the type of packing of the microfibrils in cortical cells of the two regions: ortho- and para- cortex. The type of lateral packing of the micro- fibrils must influence many properties of keratin fibres. We have discussed this problem in some detail in connection with our proposed mechanism of supercontraction in keratin (7) and have further suggested (14) that keratinization involves the stabi- lization of microfibrillar texture leading to the uniplanar cross-linking together of the microfibrils to form sheets. However, Fraser (4) and, independently, Rogers (private communication) suggested that the width (1 to 3 microns) of the sheets of microfibrils obtained by us (6, 7) may be rather due to the mode of bio- synthesis of macrofibrils; namely some "early" mi- crofibrils aggregating laterally, and their continuing to be synthesized in scroll-like fashion to form macro-fibrils. They, in fact, suggested that the chemical treatment of Jeffrey et al. (6, 7) was capable of reversing this underlying organization in the fully hardened keratin. This divergence o'i views ma\ be accounted for by the differences in chemical reactivity between the cortical cells from crimpy and straight animal fibres; a view confirmed recently by Satlow and Sikorski (13) who found that more
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