Localized induction equation and pseudospherical surfaces

We describe a close connection between the localized induction equation hierarchy of integrable evolution equations on space curves, and surfaces of constant negative Gauss curvature.Comment: 21 pages, AMSTeX file. To appear in Journal of Physics A: Mathematical and Genera

THE EXCRETION OF PORPHYRIN IN REFRACTORY AND APLASTIC ANEMIA

Technical procedures which have been developed for quantitative measurements of the rate of excretion of the porphyrins have advanced the knowledge of the fundamental nature of certain anemic states. By such studies the disorders of hematopoiesis may be divided into two major groups on a pathological-physiological basis. In one group the metabolism of the pigments is quantitatively increased but is normal in type. Pernicious anemia, congenital hemolytic jaundice, and the anemia caused by phenylhydrazine are all of this variety (1, 2, 3, 4, 5). In a second group, however, a qualitative as well as a quantitative deviation from the normal metabolism of pigments exists. The anemia of lead (6, 7, 8) an