Early man-made fibres and their raw materials, c 1930s.

UNITED KINGDOM - SEPTEMBER 25: Boxed exhibit containing samples of fibrolane, ardil and casein, and the raw materials from which they are made. Fibrolane and ardil are both natural protein fibres, fibrolane being derived from groundnuts and ardil from soya beans. Casein is a semi-synthetic plastic present in skimmed milk. A rennet is used to precipitate it out. The casein is dyed, drawn out into shapes for machining and cured by immersing it into formaldehyde. In the 1920s and 1930s it was known commercially as �Erinoid� and was used to make furniture handles, buttons and other decorative items. (Photo by SSPL/Getty Images)