are also provided application_number US 81704406 A description the invention will now be described in greater detail with reference to the following specific non limiting examples a collagen precipitate precipitated in an acid medium ph 3 which had been obtained in accordance with the method described in wo 01 64046 was separated from the medium by filtration and wrung out under pressure until a residual moisture content of approximately 84 by weight was obtained the collagen fibers obtained in this manner were freeze dried for storage at a temperature of approx 20 u00b0 c 121 g of the frozen collagen fibers were suspended in 1300 ml of aqueous 0 5 v v h 2 o 2 solution while stirring for 2 hours then the ph of the solution was adjusted to a value of 12 4 with a 5n solution of naoh in order to dissolve the collagen fibers the resulting collagen solution was filtered to remove insoluble components and then poured into 2600 ml ethanol conc 98 while stirring vigorously the collagen thereby precipitated was of a white or slightly yellowish color and had a fibrous appearance the collagen fibers were freed from the medium by filtration wrung out under pressure or by centrifugation and subsequently homogenously suspended in 300 ml of an aqueous 0 5 v v h 2 o 2 solution while stirring the ph of the solution was adjusted to a value of 6 5 with a.