1889, with disastrous results. Subsequently, in the early to mid-1900s, a number of other substances were tried, including ivory , glass balls, ground rubber , ox cartilage , Terylene wool , gutta-percha , Dicora, polyethylene chips, polyvinyl alcohol -formaldehyde polymer sponge (Ivalon), Ivalon in a polyethylene sac, polyether foam sponge (Etheron),