As is now well known, Tiselius' (1) development of the moving boundary method for electrophoresis has been of great service in the study of solutions of proteins. In that method a plane of contact is first made between a solution of the proteins in a buffer and the pure buffer. When a current is passed, under appropriate conditions, a series of boundaries is formed. With the aid of the Toepler schlieren technique these boundaries may be seen on a ground glass or may be recorded photographically. Evidence of the different boundaries consists of bands of shadow, the number of which indicate the presence of constituents having different electrophoretic mobilities (if certain "boundary anomalies" are excluded). The motions of the bands yield the values of the mobilities under the conditions of the experiment. Stenhagen (2), using this procedure, has made an extended study of human blood plasma, showing the variation of the mobilities of the different protein constituents (albumin, fibrinogen, and a,/3, and "y globufins) with the pH. However, the schlieren method, as originally used, yields no quantitative information as to the relative amounts of the proteins present. Estimates of the quantities of the various constituents in solution, as well as their mobilities and relative homogeneities, may be obtained with the aid of the Lamm "scale" method (3). In that procedure a photograph of a graduated scale is taken through the electrophoretic boundaries, and the displacement of the lines of the scale produced by variations of the refractive index is then obtained with a comparator. If the boundaries are not too sharp, i.e., if the refractive index gradients are not too great, this method yields data which may be plotted in such a way that the determination of the areas under the various "peaks" measures the concentrations. Although the method requires many hours of tedious work with a comparator, interesting and important results with the method have been obtained by Tiselius and Horsfall (4) and Tiselius and Kabat (5).
Vol. 62 catalytic thermal decomposition of (a) ethylene for the hydrogenation of acetone at 110°, (b) methane for the hydrogenation of carbon dioxide at 315°, and of nitrous oxide at 73.5°2. The experimental evidence indicates that the surface of the nickel catalysts studied was non-uniform because (a) catalysts which no longer catalyzed the decomposition reactions were still active at lower temperatures in the hydrogenation reactions, (b) certain parts of the surface were more active than others in the hydrogenation of acetone, (c) heating in hydrogen a surface upon which the hydrogenation of nitrous oxide had occurred caused selective activation or poisoning according to conditions, (d) the nickel surface responsible for about two-thirds of the hydrogenation of carbon dioxide could be poisoned without affecting the nickel surface which catalyzed the hydrogenation of nitrous oxide. Providence, R. I.
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