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The V-pattern of starch is difficult to understand. It is the x-ray pattern of starch in fresh bread; and it is the x-ray pattern of starch pastes and of starch solutions, after dehydration with alcohol. A real explanation of this x-ray pattern cannot yet be given. But a series of facts found since 1930 makes another interpretation more probable than the one published then. It now seems most likely to be the superimposition of two patterns: an amorphous pattern of starch and a purely crystalline V-pattern. But the old explanation still remains a possibility. When the new explanation is accepted, the change in the starch during the staling of bread is to be explained as the crystallization of the amorphous part of the swollen granules to a crystalline substance with a B-pattern. And, on this basis, the micels in dilute fresh starch pastes and in dilute fresh starch solutions are to be considered as being chiefly amorphous. In very concentrated pastes and solutions they may be partly crystalline (with V-pattern).

The X-ray pattern of irisin like that of inulin shows definite Intensity changes when the material is dried. This indicates that the absorption of water is predominantly intermicellar.

When one tries to characterize a starch preparation by its x-ray pattern, a more exact characterization is possible by comparing also the x-ray pattern of the dried substance. These can look like “amorphous” patterns in the case of native starches. But in other starch preparations the x-ray patterns of the dried substances may be sharp crystalline patterns. In all these cases the relative intensities of the crystalline interferences change in a characteristic way, when the substances are dried.

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The spongy product from gutta-percha hydrocarbon, which is obtained from a concentrated petroleum ether solution, consists of microcrystals of the α-modification. The difference in its solubility and that of the compressed product prepared from the spongy product is perhaps attributable to the presence of an impurity. By treatment of the fused hydrocarbon with benzene below 19° C. both the β-form and the amorphous form dissolve, and one of these forms is converted, or perhaps both of the forms are converted, into the α-form. It is possible that petroleum ether dissolves not only the amorphous form but also a part of the β-form. It does not, however, transform the β-form into the α-form. Compression in the cold of previously fused strips, as well as of strips elongated while cold, decreases the solubility of these strips in benzene below 19° C. Cold-drawing of threads, which have been prepared from fused products, has only a slight influence on the stability of the threads in benzene below 19° C.

1. In der vorliegenden Arbeit wurden die Alterungserscheinungen von 7 Starkesubstanzen unter Beobachtung der Trubung, Flockung, Viskositat, Jodfarbe, Leitfahigkeit, Malzresistenz und Rontgenspektrum verfolgt. 2. Die Anderung der Viskositat, die Trubung und Flockung sind bei den verschiedenen Starkesubstanzen verschieden und abhangig von ihrem kolloiden Zustand und ihrer chemischen Besonderheit. 3. Die Malzresistenz steigt bei allen untersuchten Produkten zeitlich an, verschieden sind die Geschwindigkeit und der Grad dieser Anderung. 4. Das Rontgenspektrum ist je nach der Art, wie die Alkoholfallung ausgefuhrt wurde, verschieden; das Auftreten des Retrogradations-spektrums wird durch die eigensaure Natur der Starkesubstanzen begunstigt. 5. Es wurde versucht, die einzelnen Alterungsanderungen von einem einheitlichen Standpunkte aus zu erklaren.

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