Abstract: Shaped articles in thin-walled form, such as threads, membranes, sheets and tubes and particularly material for encasing sausage, are produced from a shapable mass containing in aqueous dispersion at least one coagulable, amphoteric high molecular organic substance, such as collagen or other coagulable animal protein, by extruding the mass through a die into an aqueous bath in which coagulation of such substance in the extrudate is effected by changing the pH of the dispersion so that the isoelectric point of the substance is traversed, the dispersion being prepared with a sufficient content of polyvalent ions, such as calcium ions, to inhibit formation in the extrudate of a barrier to ion penetration. The dispersion desirably also contains an agent for cross-linking the coagulable substance in the extrudate. The mass fed to the extruding die preferably is a collagen paste containing glyoxal and calcium ions. The speed of the coagulation can be enhanced by subjecting the extrudate in the bath to a D.C.