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A simplified procedure for filter paper electrophoresis is described in which disturbing factors such as evaporation, heating, buffer concentration gradients, and pH changes in the electrode vessels were reduced to a minimum. Artificial mixtures of highly purified proteins could be separated and the components isolated. The application of the method to a variety of studies on serum proteins is demonstrated. Protein concentration in paper segments was determined by two different methods of protein estimation. Curves were obtained showing the same five major peaks for normal serum as found by the classical methods of free electrophoresis. Comparisons were made of the areas of the various components under the curves obtained with the different methods. Two dimensional electrophoresis was applied to serum and serum components. It proved of value in demonstrating the heterogeneity of fractions such as the γ-globulin of serum. The polysaccharide dextran was used as an index of the extent of electro-osmotic flow during the course of the various experiments. The ratio of the distance of electroosmotic flow and the distance of protein migration was shown to be constant for a given type of paper. For serum albumin on Munktell 20 paper this ratio was 0.35. A formula for mobilities applicable to liquid in a highly porous supporting medium is presented. Mobility values for human serum albumin at various pH levels on paper showed approximate agreement with those obtained in free solution giving a similar isoelectric point.

A method is suggested for the sampling of sulfur dioxide in air with impregnated filter paper instead of bubblers. The best aqueous impregnating solution contained potassium hydroxide with glycerol or triethanolamine. The possibilities and limitations of the method are discussed. High collection efficiencies (over 95%) were obtained at relative humidities above 25%. Collected sulfur dioxide was stable for at least several weeks when the filters were kept dry after the sampling. The method is especially suited for short-time measurements and for automatic sampling with smoke samplers.

The presence of the short-term C/sup 14/-labeled fluorescent compound in photosynthesis previously reported as a pteridine was determined to be a result of the technique employed in the experiments and not a metabolic reality in photosynthesis. (C.H.)

The growth inhibition test for identifying Mycoplasma species has been modified by drying antibody-impregnated paper discs at 5 C. When stored at −20 C, these discs have been found to retain their inhibitory activity for longer than 7 months. Since these discs can be stored for long period of time, significant advantages over present methods result. When, for example, discs are arranged on a ring, a single test can be used for the identification of an unknown human species. Valuable antisera can be distributed to other laboratories on paper discs in much less volume than can fluid antiserum. Considerable savings of time result from prior preparation of many discs that can then be stored and used over a long period of time. The growth-inhibiting antibody is stable, and the activity is not enhanced by a heat-labile accessory factor from fresh guinea pig serum which increases the antibody titer in the metabolic inhibition test.

Microbiological assay of individual antibiotics in mixtures of antibiotics depends on the use of selective inactivation and/or of test bacteria with differential susceptibility. Controlled experiments revealed that streptomycin in concentrations of 20 and 40 μg/ml did not influence a disk diffusion assay of penicillin with Sarcina lutea (ATCC 9341) as the test organism. In the case of penicillin concentrations less than or equal to 1 IU/ml, addition of 80 μg of streptomycin per ml influenced the penicillin assay significantly. Clinical use of streptomycin resulting in levels above 40 μg/ml usually did not occur; therefore penicillin could be assayed as though streptomycin were not present. We observed additionally that S. lutea was unable to grow on agar plates prepared with semicarbazide hydrochloride.

A notable advance in knowledge may raise as many questions as it solves, and a period of intensive and fruitful research may at first sight seem to leave us as far as ever from the solution of the problem we are in vestigating. This might plausibly be said of poliomyelitis. Few affections of the nervous system have been more closely or successfully studied within the past few years, yet fresh pathological and epid?miological factors appear for elucidation, effective therapy remains as remote as ever, and many of our earlier certitudes have gone by the board. Yet we must necessarily be nearer a grasp of the many problems presented by poliomyelitis, and the present time is appropriate for a review of some recent advances in our knowledge. A comprehensive summary of these is not possible within the limits of my present opportunity, and I propose, therefore, to confine myself to a brief consideration of the question of the specific treatment of the disease in the light of our rapidly changing conception of its nature. By way of definition we may say that poliomyelitis is one of a small group of infections of the nervous systems due to the action of ultra-microscopic viruses, the morpho logical identities of which are unknown to us. Other examples of the group are epidemic encephalitis and rabies, and in all three it is the grey matter which is the point of attack, whence these viruses are spoken of as " polioclastic." Of the characteristics they have in common perhaps the most striking are that they multiply only in contact with the living cell, within which their life and activity appear to be very brief, for after a short period they disappear. To this disappearance the name " auto-sterilization " has been applied, and in consequence of it virus diseases may be spoken of as " self-limiting."