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A number of the important physical and chemical properties of wool are closely associated with the presence of disulfi de cross-linkages between the polypeptide chains of the protein. This conclusion results from a study of the behavior of wool before and after alteration of the mode of linkage of the sulfur by a series of highly specific reactions.The cystine in wool can be readily reduced to cysteine with thioglycolic acid. Strongly alkaline solutions of the reagent have been shown by previous investigators t o dissolve the protein and destroy its fibro us structure. It is now shown that wool can be reduced with thioglycolic acid over a wide range of pH, and that when the reduction is carried out in neutral or acid solution, the fib rous structure of the wool is not destroyed when the disulfide groups are reduced to sulfhydryl groups. T he sulfhydryl groups of fibers reduced in this way react readily with alkyl halides to form thioether groups.Thus reaction of reduced wool with alkyl monohalides, such as methyl iodide, results in permanent rupture of disulfide linkages, and the fibers are greatly increased in extensibility and decreased in strength. Alkylation with aliphatic dihalides, such as methylene iodide or trilnethylene dibromide, introduces hydrocarbon chains between pairs of sulfur atoms of cystine molecules in the fibers. Such fibers are very similar to untreated fibers in physical properties.Wool in which the disulfide linkages have been broken by reduction, or by reduction and alkylation with alkyl monohalides, possesses much higher alkalisolubility t han untreated wool, while wool in which the disulfide cross-linkages have been replaced by new covalent cross-linkages through reduction followed by alkylation with dihalides possesses m uch lower alkali-solubility. Since th!' susceptibility of wool to degradation by alkalies is one of its greatest disadvantages, p rocesses that would make it stable toward alkalies should also enhance its durability. CONTENTS

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Suspensions of solvent-extracted Idaho and Australian raw wool and of scoured worsted cloth in buffer solutions of different pH were prepared by grinding the dry wool to a fine powder and shaking the powder in the buffer solution. Electrophoretic measurements of these suspensions gave an isoelectric point for each wool at pH 3.4.

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