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Structures of Carbides, Nitrides and Oxides of Uranium 99 passed through the reactor at 235°. The effluent gaseous products of the reaction were found to be as follows Propylene Per cent.

For many years the chemical literature has contained references to starch fractionation. The methods employed have been numerous and the products obtained by different methods have generally been at variance in their chemical and physical properties.2Recently, however, three methods of fractionation have been developed which appear to give nearly identical results. The methods are (a) hot water extraction of one component,* (b) selective adsorption of this same component on cellulose,4 and (c) the selective precipitation of this component by butanol and other alcohols.6In each case one fraction stains blue with iodine, is converted almost completely to maltose by /3-amylase, retrogrades easily, and furnishes good quality X-ray diffraction patterns in "A," " " and "V" modifications. The other fraction stains purple to red with iodine, is only partially converted to maltose by (3-amylase, retrogrades with difficulty or not at all, and yields poor or even amorphous diffraction patterns regardless of treatment.Meyer has made a thorough study of the two components of his fractionation,6 and has concluded that the hot-water extracted fraction is straight-chain starch, i. e,, glucose residues united exclusively by a-l,4-glucosidic linkages, the other fraction is similar but highly branched, probably through a-l,6-glucosidic linkages.7 He has used the term, "amylose" to designate the straightchain fraction, and "amylopectin," the branchedchain fraction.* At the present time the proof of the structure of the two starch components is based almost entirely upon quantitative methylation studies. These are executed only with difficulty and can