(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.

    22/30 (page 302)
    2. The toxin goes through the best and thickest parchment commercially obtainable, though the parchment is far less permeable to water than the collodion membrane through which toxin cannot pass. A large volume of toxin J 2536 (L+ dose = 0*35 cc.) filtered through parchment under a slight pressure yielded after some days 50 cc. of filtrate resembling the original in colour and general precipitation reactions. The L+ dose of the filtrate was 0*60 cc. This is a striking example of the fact that low permeability of a membrane to water is not necessarily accompanied by low permeability to toxin. Using the same batch of toxin and a collodion membrane (m— 5: w = 3*5, [see Walpole, 1915]) no toxin could be detected in the filtrate (1 cc. nil), though the volume of the filtrate per square centimetre per hour was many times greater in this case. Below are given details of a repetition of this experiment, using another sample of the parchment and another collodion bag. Collodion bag. Area exposed 260 sq. cm. Time 24 hours. Filtrate 8 cc., of which 1 cc. has no effect on the guinea pig. Pressure 6 water. Parchment bag. Area exposed 1960 sq. cm. Time 24 hours. Filtrate 6 cc. of which 0*1 cc. kills a guinea pig. Pressure 7 water. This point is, in our opinion, worth full and patient investigation because of its far-reaching consequences in bacteriological work generally. 3. The amount of toxin in a cultural filtrate bears no relation to the amount of precipitate obtained on acidification after pressure dialysis through these membranes. 4. The method is universally applicable at least to all brews of diphtheria toxin of the type made in these laboratories. Samples of 200 cc. each from twenty-nine different brews of toxin were dialysed, each in a separate bag, under pressure for four days against distilled water changed daily. Colouring matter had then ceased to come out through the bags and the specific conductivity of the inside fluid was in every case less than 78 x 10-5. All gave nicely flocculated precipitates on adding 6 cc. of 1*0 N acetic acid to the contents of each bag. They were placed in order of the amounts of their precipitates as well as could be judged by eye. The first fifteen precipitates were then mixed and dissolved in 60 cc. of distilled water. Equal volumes of the corresponding original brews were also mixed. Both solutions were tested for “binding units” with the following results. The first fifteen samples amounted in volume to 3000 cc. (L+ dose = 0*45), from which were obtained 60 cc. of concentrated material (L+ dose = 0*012).