This toothbrush is flat, but it used to contain Siberian boar (male pig) hair that was tough enough for cleaning teeth. A manufacturer carved animal bone into the shape of this toothbrush. They tied the boar hair into tiny bundles, inserted them through the holes, and glued them into place. If the hairs fell out over time, a person could use the slits on the back side to replace the hairs. Archaeologists found over 80 toothbrushes in the Market Street Chinatown. Toothbrushes like this one, with four rows of bristles, were usually made in China, while those with three rows were made in the United States. For more information, visit http://www.chinesemuseum.historysanjose.org/digital-exhibits/chinatownhere/object-gallery/toothbrushes/.