Source for collagen

Would anyone know where one can order collagen membrane, skin
membrane or goldbeater's skin? this would be to repair a skin.  I
searched DistList archives in CoOL for these 3 terms but no supplier
came up.

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                  Conservation DistList Instance 12:51
                Distributed: Tuesday, December 15, 1998
                       Message Id: cdl-12-51-026
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