(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?]
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.
6/30 page 286
![to the other are none of them sufficiently large to let the antigen pass, but there are many of them. On the other hand, it is suggested that m parchment, for example, these holes are of irregular size. Some are large enough to let diphtheria toxin through, but the total amount of water they will allow to pass is, in virtue of the lower general porosity of the structure, less in this case [Glenny and Walpole, 1915]. Collodion used. As a stock solution a 14 per cent, solution by weight of Schering’s celloidin in equal parts of alcohol and ether was originally employed. Later the British Xylonite Company have kindly supplied me with a similar material ready dissolved and filtered clear. It is named for reference F 4241 A and supplied by them in tins with convenient screwed stoppers at a price which represents a considerable saving in expense. The solutions when used in the same manner give very similar results as may be judged from the comparative experiments given below (page 287). The preparation of collodion bags. These have been often described by Malfitano [1904], Bigelow [1907] and many other authors. That they may be made with differences of porosity is generally known. For information about them and instructions how to make them I am indebted to Prof. S. P. L. Sorensen and Dr Christiansen. They are sometimes made by pouring con¬ secutive layers of the solution on to the outside of a test tube rotated by a suitable mechanism. Probably the bags made in this way are more perfect than those made inside test tubes, but special apparatus is required and, I should judge, considerable experience and skill in order to be sure of producing a bag of just the required impermeability. The following is a description of the bags which I have adopted as “standard,” though for anything beyond odd quantitative experiments I prefer to use the flat sheets described in some detail later, for they possess certain advantages over any cylindrical bag however perfect. A test tube is filled with “stock solution,” capped with tin foil and after the twelve or fifteen hours required for the bubbles to rise is inverted and clamped so that the mouth is well above the wide mouthed stock bottle. When the flow of collodion ceases the bottle is removed and stoppered and about ten minutes later the drippings are cut away from the test tube with a sharp knife, care being taken not to pull loose the lower edge of its collodion lining. The test tube must, of course, be cut off sharp and not lipped or opened at the mouth in any way. Drying is allowed to continue until the inside when rubbed gently with the finger does not mark at all—a degree which cannot be described precisely—a process taking about half an hour at](https://iiif.wellcomecollection.org/image/b30621355_0006.jp2/full/800%2C/0/default.jpg)
