(1) Notes on colloidon membranes for ultrfiltration and pressure dialysis / by G.S. Walpole. (2) Detection and concentration of antigens by ultrafiltration, pressure dialysis, etc., with special reference to diphtheria and tetanus toxins / by A.T. Glenny and G.S. Walpole.

  • Walpole, George Stanley.
Date:
[1915?]
Catalogue details

Licence: In copyright

Credit: (1) Notes on colloidon membranes for ultrfiltration and pressure dialysis / by G.S. Walpole. (2) Detection and concentration of antigens by ultrafiltration, pressure dialysis, etc., with special reference to diphtheria and tetanus toxins / by A.T. Glenny and G.S. Walpole. Source: Wellcome Collection.

    27/30 (page 307)
    Filtration of 'pituitary active principle, etc. Although they are not antigens, the behaviour of secretin and the active principle of pituitary extract when filtered under pressure through these bags is of considerable interest. A simple pituitary extract gave a filtrate which, compared with the original solution and the residue, showed that although much of the active principle had passed through it had not done so at the same rate as the water, salts, etc. A similar result was obtained with the co-enzyme of zymase, in an experiment in conjunction with Prof. Harden, to whom I am indebted for the material and the tests. Dr P. P. Laidlaw has communicated to me privately that one of his secretin preparations, filtered through a standard bag into saturated picric acid, gave at once a crystalline precipitate of marked activity. I wish to express my indebtedness to the assistance of Mr Ralph Defries during the course of this work. Summary. Experiments are described in which the permeability of collodion-water membranes of a special type to various antigens was investigated. Owing to the fact that none of the antigens tried was found to pass through these membranes their use is suggested for the purpose of forming a first opinion as to the specificity or otherwise of the toxic element of any cultural fluid. The recognition and subsequent concentration of the antigen of a fatal epidemic in the squirrel was effected by this means, and an investigation of the nature of the toxicity of filtrates of malignant oedema cultures led to its complete elucidation. Mallein and tuberculin were freed from glycerol and a considerable quantity of nitrogenous material in this way. A process for the concentration and purification of diphtheria toxin which at a yield of 70-80 per cent, diminishes the nitrogen content about 50 times has been fully worked out. It is performed by dialysis under pressure, followed by acidification, centrifugalisation, and re-solution of the small precipitate obtained in a trace of alkali. If a continual supply of toxin having L+ dose 0*20 could be relied upon, this artificial conversion of low value toxin to that of high titre, would remain more of academic than practical interest. But, the majority of batches do not reach this high level and hence this concentration